diff --git a/docs/references/function-list-by-category.md b/docs/references/function-list-by-category.md
index e6a702028..25dde055f 100644
--- a/docs/references/function-list-by-category.md
+++ b/docs/references/function-list-by-category.md
@@ -251,6 +251,7 @@ FORMULATEXT              | \PhpOffice\PhpSpreadsheet\Calculation\LookupRef\Formu
 GETPIVOTDATA             | **Not yet Implemented**
 GROUPBY                  | **Not yet Implemented**
 HLOOKUP                  | \PhpOffice\PhpSpreadsheet\Calculation\LookupRef\HLookup::lookup
+HSTACK                   | \PhpOffice\PhpSpreadsheet\Calculation\LookupRef\Hstack::hstack
 HYPERLINK                | \PhpOffice\PhpSpreadsheet\Calculation\LookupRef\Hyperlink::set
 INDEX                    | \PhpOffice\PhpSpreadsheet\Calculation\LookupRef\Matrix::index
 INDIRECT                 | \PhpOffice\PhpSpreadsheet\Calculation\LookupRef\Indirect::INDIRECT
@@ -266,6 +267,7 @@ TAKE                     | \PhpOffice\PhpSpreadsheet\Calculation\LookupRef\Choos
 TRANSPOSE                | \PhpOffice\PhpSpreadsheet\Calculation\LookupRef\Matrix::transpose
 UNIQUE                   | \PhpOffice\PhpSpreadsheet\Calculation\LookupRef\Unique::unique
 VLOOKUP                  | \PhpOffice\PhpSpreadsheet\Calculation\LookupRef\VLookup::lookup
+VSTACK                   | \PhpOffice\PhpSpreadsheet\Calculation\LookupRef\Vstack::vstack
 XLOOKUP                  | **Not yet Implemented**
 XMATCH                   | **Not yet Implemented**
 
@@ -308,7 +310,6 @@ FLOOR                    | \PhpOffice\PhpSpreadsheet\Calculation\MathTrig\Floor:
 FLOOR.MATH               | \PhpOffice\PhpSpreadsheet\Calculation\MathTrig\Floor::math
 FLOOR.PRECISE            | \PhpOffice\PhpSpreadsheet\Calculation\MathTrig\Floor::precise
 GCD                      | \PhpOffice\PhpSpreadsheet\Calculation\MathTrig\Gcd::evaluate
-HSTACK                   | **Not yet Implemented**
 INT                      | \PhpOffice\PhpSpreadsheet\Calculation\MathTrig\IntClass::evaluate
 ISO.CEILING              | **Not yet Implemented**
 LCM                      | \PhpOffice\PhpSpreadsheet\Calculation\MathTrig\Lcm::evaluate
@@ -360,7 +361,6 @@ TANH                     | \PhpOffice\PhpSpreadsheet\Calculation\MathTrig\Trig\T
 TOCOL                    | **Not yet Implemented**
 TOROW                    | **Not yet Implemented**
 TRUNC                    | \PhpOffice\PhpSpreadsheet\Calculation\MathTrig\Trunc::evaluate
-VSTACK                   | **Not yet Implemented**
 WRAPCOLS                 | **Not yet Implemented**
 WRAPROWS                 | **Not yet Implemented**
 
diff --git a/docs/references/function-list-by-name-compact.md b/docs/references/function-list-by-name-compact.md
index b5f81b059..48ee91be0 100644
--- a/docs/references/function-list-by-name-compact.md
+++ b/docs/references/function-list-by-name-compact.md
@@ -259,7 +259,7 @@ HEX2DEC                  | ENGINEERING           | Engineering\ConvertHex::toDec
 HEX2OCT                  | ENGINEERING           | Engineering\ConvertHex::toOctal
 HLOOKUP                  | LOOKUP_AND_REFERENCE  | LookupRef\HLookup::lookup
 HOUR                     | DATE_AND_TIME         | DateTimeExcel\TimeParts::hour
-HSTACK                   | MATH_AND_TRIG         | **Not yet Implemented**
+HSTACK                   | LOOKUP_AND_REFERENCE  | LookupRef\Hstack::hstack
 HYPERLINK                | LOOKUP_AND_REFERENCE  | LookupRef\Hyperlink::set
 HYPGEOM.DIST             | STATISTICAL           | **Not yet Implemented**
 HYPGEOMDIST              | STATISTICAL           | Statistical\Distributions\HyperGeometric::distribution
@@ -619,7 +619,7 @@ VARP                     | STATISTICAL           | Statistical\Variances::VARP
 VARPA                    | STATISTICAL           | Statistical\Variances::VARPA
 VDB                      | FINANCIAL             | **Not yet Implemented**
 VLOOKUP                  | LOOKUP_AND_REFERENCE  | LookupRef\VLookup::lookup
-VSTACK                   | MATH_AND_TRIG         | **Not yet Implemented**
+VSTACK                   | LOOKUP_AND_REFERENCE  | LookupRef\Vstack::vstack
 
 ## W
 
diff --git a/docs/references/function-list-by-name.md b/docs/references/function-list-by-name.md
index c2ece937a..2e183f15e 100644
--- a/docs/references/function-list-by-name.md
+++ b/docs/references/function-list-by-name.md
@@ -255,7 +255,7 @@ HEX2DEC                  | CATEGORY_ENGINEERING           | \PhpOffice\PhpSpread
 HEX2OCT                  | CATEGORY_ENGINEERING           | \PhpOffice\PhpSpreadsheet\Calculation\Engineering\ConvertHex::toOctal
 HLOOKUP                  | CATEGORY_LOOKUP_AND_REFERENCE  | \PhpOffice\PhpSpreadsheet\Calculation\LookupRef\HLookup::lookup
 HOUR                     | CATEGORY_DATE_AND_TIME         | \PhpOffice\PhpSpreadsheet\Calculation\DateTimeExcel\TimeParts::hour
-HSTACK                   | CATEGORY_MATH_AND_TRIG         | **Not yet Implemented**
+HSTACK                   | CATEGORY_LOOKUP_AND_REFERENCE  | \PhpOffice\PhpSpreadsheet\Calculation\LookupRef\Hstack::hstack
 HYPERLINK                | CATEGORY_LOOKUP_AND_REFERENCE  | \PhpOffice\PhpSpreadsheet\Calculation\LookupRef\Hyperlink::set
 HYPGEOM.DIST             | CATEGORY_STATISTICAL           | **Not yet Implemented**
 HYPGEOMDIST              | CATEGORY_STATISTICAL           | \PhpOffice\PhpSpreadsheet\Calculation\Statistical\Distributions\HyperGeometric::distribution
@@ -615,7 +615,7 @@ VARP                     | CATEGORY_STATISTICAL           | \PhpOffice\PhpSpread
 VARPA                    | CATEGORY_STATISTICAL           | \PhpOffice\PhpSpreadsheet\Calculation\Statistical\Variances::VARPA
 VDB                      | CATEGORY_FINANCIAL             | **Not yet Implemented**
 VLOOKUP                  | CATEGORY_LOOKUP_AND_REFERENCE  | \PhpOffice\PhpSpreadsheet\Calculation\LookupRef\VLookup::lookup
-VSTACK                   | CATEGORY_MATH_AND_TRIG         | **Not yet Implemented**
+VSTACK                   | CATEGORY_LOOKUP_AND_REFERENCE  | \PhpOffice\PhpSpreadsheet\Calculation\LookupRef\Vstack::vstack
 
 ## W
 
diff --git a/src/PhpSpreadsheet/Calculation/FunctionArray.php b/src/PhpSpreadsheet/Calculation/FunctionArray.php
index 0692d34a8..0813cee8b 100644
--- a/src/PhpSpreadsheet/Calculation/FunctionArray.php
+++ b/src/PhpSpreadsheet/Calculation/FunctionArray.php
@@ -1106,8 +1106,8 @@ class FunctionArray extends CalculationBase
             'argumentCount' => '1',
         ],
         'HSTACK' => [
-            'category' => Category::CATEGORY_MATH_AND_TRIG,
-            'functionCall' => [Functions::class, 'DUMMY'],
+            'category' => Category::CATEGORY_LOOKUP_AND_REFERENCE,
+            'functionCall' => [LookupRef\Hstack::class, 'hstack'],
             'argumentCount' => '1+',
         ],
         'HYPERLINK' => [
@@ -2569,8 +2569,8 @@ class FunctionArray extends CalculationBase
             'argumentCount' => '3,4',
         ],
         'VSTACK' => [
-            'category' => Category::CATEGORY_MATH_AND_TRIG,
-            'functionCall' => [Functions::class, 'DUMMY'],
+            'category' => Category::CATEGORY_LOOKUP_AND_REFERENCE,
+            'functionCall' => [LookupRef\Vstack::class, 'vstack'],
             'argumentCount' => '1+',
         ],
         'WEBSERVICE' => [
diff --git a/src/PhpSpreadsheet/Calculation/LookupRef/Hstack.php b/src/PhpSpreadsheet/Calculation/LookupRef/Hstack.php
new file mode 100644
index 000000000..9be77e5c5
--- /dev/null
+++ b/src/PhpSpreadsheet/Calculation/LookupRef/Hstack.php
@@ -0,0 +1,48 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\LookupRef;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Calculation\Information\ExcelError;
+
+class Hstack
+{
+    /**
+     * Excel function HSTACK.
+     *
+     * @return mixed[]|string
+     */
+    public static function hstack(mixed ...$inputData): array|string
+    {
+        $maxRow = 0;
+        foreach ($inputData as $matrix) {
+            if (!is_array($matrix)) {
+                $count = 1;
+            } else {
+                $count = count($matrix);
+            }
+            $maxRow = max($maxRow, $count);
+        }
+        /** @var mixed[] $inputData */
+        foreach ($inputData as &$matrix) {
+            if (!is_array($matrix)) {
+                $matrix = [$matrix];
+            }
+            $rows = count($matrix);
+            $reset = reset($matrix);
+            $columns = is_array($reset) ? count($reset) : 1;
+            while ($maxRow > $rows) {
+                $matrix[] = array_pad([], $columns, ExcelError::NA());
+                ++$rows;
+            }
+        }
+
+        $transpose = array_map(null, ...$inputData); //* @phpstan-ignore-line
+        $returnMatrix = [];
+        foreach ($transpose as $array) {
+            $returnMatrix[] = Functions::flattenArray($array);
+        }
+
+        return $returnMatrix;
+    }
+}
diff --git a/src/PhpSpreadsheet/Calculation/LookupRef/Vstack.php b/src/PhpSpreadsheet/Calculation/LookupRef/Vstack.php
new file mode 100644
index 000000000..919c262a5
--- /dev/null
+++ b/src/PhpSpreadsheet/Calculation/LookupRef/Vstack.php
@@ -0,0 +1,42 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\LookupRef;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Information\ExcelError;
+
+class Vstack
+{
+    /**
+     * Excel function VSTACK.
+     *
+     * @return mixed[]
+     */
+    public static function vstack(mixed ...$inputData): array|string
+    {
+        $returnMatrix = [];
+
+        $columns = 0;
+        foreach ($inputData as $matrix) {
+            if (!is_array($matrix)) {
+                $count = 1;
+            } else {
+                $count = count(reset($matrix)); //* @phpstan-ignore-line
+            }
+            $columns = max($columns, $count);
+        }
+
+        foreach ($inputData as $matrix) {
+            if (!is_array($matrix)) {
+                $matrix = [$matrix];
+            }
+            foreach ($matrix as $row) {
+                if (!is_array($row)) {
+                    $row = [$row];
+                }
+                $returnMatrix[] = array_values(array_pad($row, $columns, ExcelError::NA()));
+            }
+        }
+
+        return $returnMatrix;
+    }
+}
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/LookupRef/HStackTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/LookupRef/HStackTest.php
new file mode 100644
index 000000000..e539c7da5
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/LookupRef/HStackTest.php
@@ -0,0 +1,94 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\LookupRef;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Calculation;
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+
+/**
+ * Many of these tests are derived from
+ * https://exceljet.net/functions/hstack-function.
+ */
+class HStackTest extends AllSetupTeardown
+{
+    public static function testHstack1(): void
+    {
+        $spreadsheet = new Spreadsheet();
+        Calculation::getInstance($spreadsheet)
+            ->setInstanceArrayReturnType(
+                Calculation::RETURN_ARRAY_AS_ARRAY
+            );
+        $sheet = $spreadsheet->getActiveSheet();
+        $b4tof14 = [
+            ['A', null, 'B', null, 'C'],
+            [12, null, 7, null, 12],
+            [9, null, 13, null, 10],
+            [10, null, 5, null, 11],
+            [11, null, 13, null, 6],
+            [8, null, 12, null, 7],
+            [12, null, 11, null, 15],
+            [9, null, 10, null, 6],
+            [10, null, 15, null, 5],
+            [11, null, 9, null, 14],
+            [6, null, 13, null, 11],
+        ];
+        $sheet->fromArray($b4tof14, null, 'B4', true);
+        $sheet->setCellValue('H4', '=HSTACK(B4:B14,D4:D14,F4:F14)');
+        $expected = [
+            ['A', 'B', 'C'],
+            [12, 7, 12],
+            [9, 13, 10],
+            [10, 5, 11],
+            [11, 13, 6],
+            [8, 12, 7],
+            [12, 11, 15],
+            [9, 10, 6],
+            [10, 15, 5],
+            [11, 9, 14],
+            [6, 13, 11],
+        ];
+        self::assertSame($expected, $sheet->getCell('H4')->getCalculatedValue());
+
+        $sheet->setCellValue('K4', '=HSTACK(B4:B14,D4:D12,F4:F14)');
+        $expected = [
+            ['A', 'B', 'C'],
+            [12, 7, 12],
+            [9, 13, 10],
+            [10, 5, 11],
+            [11, 13, 6],
+            [8, 12, 7],
+            [12, 11, 15],
+            [9, 10, 6],
+            [10, 15, 5],
+            [11, '#N/A', 14],
+            [6, '#N/A', 11],
+        ];
+        self::assertSame($expected, $sheet->getCell('K4')->getCalculatedValue(), 'one short column');
+
+        $sheet->setCellValue('R4', '=IFERROR(HSTACK(B4:B14,D4:D12,F4:F14),"")');
+        $expected = [
+            ['A', 'B', 'C'],
+            [12, 7, 12],
+            [9, 13, 10],
+            [10, 5, 11],
+            [11, 13, 6],
+            [8, 12, 7],
+            [12, 11, 15],
+            [9, 10, 6],
+            [10, 15, 5],
+            [11, '', 14],
+            [6, '', 11],
+        ];
+        self::assertSame($expected, $sheet->getCell('R4')->getCalculatedValue(), 'one short column with null string instead of N/A');
+
+        $sheet->setCellValue('N4', '=HSTACK(B5,H6:J6)');
+        $expected = [
+            [12, 9, 13, 10],
+        ];
+        self::assertSame($expected, $sheet->getCell('N4')->getCalculatedValue(), 'one single-cell arg');
+
+        $spreadsheet->disconnectWorksheets();
+    }
+}
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/LookupRef/VStackTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/LookupRef/VStackTest.php
new file mode 100644
index 000000000..2037bb70b
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/LookupRef/VStackTest.php
@@ -0,0 +1,175 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\LookupRef;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Calculation;
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+use PhpOffice\PhpSpreadsheet\Worksheet\Table;
+
+/**
+ * Many of these tests are derived from
+ * https://exceljet.net/functions/vstack-function.
+ */
+class VStackTest extends AllSetupTeardown
+{
+    public static function testVstack1(): void
+    {
+        $spreadsheet = new Spreadsheet();
+        Calculation::getInstance($spreadsheet)
+            ->setInstanceArrayReturnType(
+                Calculation::RETURN_ARRAY_AS_ARRAY
+            );
+        $sheet = $spreadsheet->getActiveSheet();
+        $sheet->setCellValue('B2', 'Array1');
+        $sheet->setCellValue('B3', 'Red');
+        $sheet->setCellValue('B4', 'Blue');
+        $sheet->setCellValue('B5', 'Green');
+        $sheet->setCellValue('B7', 'Array2');
+        $sheet->setCellValue('B8', 'Green');
+        $sheet->setCellValue('B9', 'Red');
+        $sheet->setCellValue('D2', 'Result');
+        $sheet->setCellValue('D3', '=VSTACK(B3:B5,B8:B9)');
+        $expected = [
+            ['Red'],
+            ['Blue'],
+            ['Green'],
+            ['Green'],
+            ['Red'],
+        ];
+        self::assertSame($expected, $sheet->getCell('D3')->getCalculatedValue());
+
+        $sheet->setCellValue('F2', '=VSTACK(B2,B8:B9)');
+        $expected = [
+            ['Array1'],
+            ['Green'],
+            ['Red'],
+        ];
+        self::assertSame($expected, $sheet->getCell('F2')->getCalculatedValue(), 'one single-cell argument');
+
+        $spreadsheet->disconnectWorksheets();
+    }
+
+    public static function testVstack2(): void
+    {
+        $spreadsheet = new Spreadsheet();
+        Calculation::getInstance($spreadsheet)
+            ->setInstanceArrayReturnType(
+                Calculation::RETURN_ARRAY_AS_ARRAY
+            );
+        $sheet = $spreadsheet->getActiveSheet();
+        $sheet->setCellValue('B3', 'Red');
+        $sheet->setCellValue('B4', 'Blue');
+        $sheet->setCellValue('B5', 'Green');
+        $sheet->setCellValue('B6', 'Blue');
+        $sheet->setCellValue('B7', 'Red');
+        $sheet->setCellValue('C3', 12);
+        $sheet->setCellValue('C4', 9);
+        $sheet->setCellValue('C5', 10);
+        $sheet->setCellValue('C5', 10);
+        $sheet->setCellValue('C6', 11);
+        $sheet->setCellValue('C7', 8);
+        $sheet->setCellValue('E3', '=VSTACK({"Color","Qty"},B3:C7)');
+        $expected = [
+            ['Color', 'Qty'],
+            ['Red', 12],
+            ['Blue', 9],
+            ['Green', 10],
+            ['Blue', 11],
+            ['Red', 8],
+        ];
+        self::assertSame($expected, $sheet->getCell('E3')->getCalculatedValue());
+        $sheet->setCellValue('A1', 'Purple');
+        $sheet->setCellValue('A2', 'Orange');
+        $sheet->setCellValue('H3', '=VSTACK({"Color","Qty"},A1:A2,B3:C7)');
+        $expected = [
+            ['Color', 'Qty'],
+            ['Purple', '#N/A'],
+            ['Orange', '#N/A'],
+            ['Red', 12],
+            ['Blue', 9],
+            ['Green', 10],
+            ['Blue', 11],
+            ['Red', 8],
+        ];
+        self::assertSame($expected, $sheet->getCell('H3')->getCalculatedValue());
+        $spreadsheet->disconnectWorksheets();
+    }
+
+    /**
+     * Excel has a problem here.
+     * If it reads VSTACK(Table1, Table2) without square
+     * brackets after Table1/2, it calculates the result as #NAME?.
+     * You can then just edit the formula without making
+     * any changes, and it will calculate it correctly,
+     * but it will add in the brackets when saving.
+     * This seems pretty buggy to me.
+     * PhpSpreadsheet will handle the formula with or without
+     * the brackets, but you should specify them to avoid
+     * problems with Excel.
+     */
+    public static function testTables(): void
+    {
+        $spreadsheet = new Spreadsheet();
+        Calculation::getInstance($spreadsheet)
+            ->setInstanceArrayReturnType(
+                Calculation::RETURN_ARRAY_AS_ARRAY
+            );
+        $sheet = $spreadsheet->getActiveSheet();
+
+        $data = [
+            ['Date', 'Color', 'Qty'],
+            [Date::stringToExcel('2021-04-03'), 'Red', 12],
+            [Date::stringToExcel('2021-04-07'), 'Blue', 9],
+            [Date::stringToExcel('2021-04-11'), 'Green', 10],
+            [Date::stringToExcel('2021-04-15'), 'Blue', 11],
+            [Date::stringToExcel('2021-04-20'), 'Red', 8],
+        ];
+        $sheet->fromArray($data, null, 'B4', true);
+        $table = new Table('B4:D9', 'Table1');
+        $sheet->addTable($table);
+
+        $data = [
+            ['Date', 'Color', 'Qty'],
+            [Date::stringToExcel('2021-05-05'), 'Red', 12],
+            [Date::stringToExcel('2021-05-12'), 'Blue', 9],
+            [Date::stringToExcel('2021-05-18'), 'Green', 10],
+            [Date::stringToExcel('2021-05-21'), 'Blue', 11],
+            [Date::stringToExcel('2021-05-28'), 'Green', 6],
+        ];
+        $sheet->fromArray($data, null, 'B11', true);
+        $table = new Table('B11:D16', 'Table2');
+        $sheet->addTable($table);
+
+        $sheet->setCellValue('G4', 'Date');
+        $sheet->setCellValue('H4', 'Color');
+        $sheet->setCellValue('I4', 'Qty');
+        $sheet->setCellValue('G5', '=VSTACK(Table1[],Table2[])');
+        $sheet->getCell('G5')->getCalculatedValue();
+
+        $sheet->getStyle('B4:B16')
+            ->getNumberFormat()
+            ->setFormatCode('d-mmm');
+        $sheet->getStyle('G5:G14')
+            ->getNumberFormat()
+            ->setFormatCode('d-mmm');
+        $expected = [
+            ['3-Apr', 'Red', '12'],
+            ['7-Apr', 'Blue', '9'],
+            ['11-Apr', 'Green', '10'],
+            ['15-Apr', 'Blue', '11'],
+            ['20-Apr', 'Red', '8'],
+            ['5-May', 'Red', '12'],
+            ['12-May', 'Blue', '9'],
+            ['18-May', 'Green', '10'],
+            ['21-May', 'Blue', '11'],
+            ['28-May', 'Green', '6'],
+        ];
+        $actual = $sheet->rangeToArray('G5:I14', null, true, true);
+        self::assertSame($expected, $actual);
+
+        $spreadsheet->disconnectWorksheets();
+    }
+}