diff --git a/src/PhpSpreadsheet/Spreadsheet.php b/src/PhpSpreadsheet/Spreadsheet.php
index fa8cbcca7a..bc1a103df6 100644
--- a/src/PhpSpreadsheet/Spreadsheet.php
+++ b/src/PhpSpreadsheet/Spreadsheet.php
@@ -701,7 +701,7 @@ public function getSheetByName($worksheetName)
     {
         $worksheetCount = count($this->workSheetCollection);
         for ($i = 0; $i < $worksheetCount; ++$i) {
-            if ($this->workSheetCollection[$i]->getTitle() === trim($worksheetName, "'")) {
+            if (strcasecmp($this->workSheetCollection[$i]->getTitle(), trim($worksheetName, "'")) === 0) {
                 return $this->workSheetCollection[$i];
             }
         }
diff --git a/tests/PhpSpreadsheetTests/SpreadsheetTest.php b/tests/PhpSpreadsheetTests/SpreadsheetTest.php
index fe4e986439..12fe4abcb1 100644
--- a/tests/PhpSpreadsheetTests/SpreadsheetTest.php
+++ b/tests/PhpSpreadsheetTests/SpreadsheetTest.php
@@ -70,11 +70,22 @@ public function testAddSheetDuplicateTitle(): void
     {
         $spreadsheet = $this->getSpreadsheet();
         $this->expectException(Exception::class);
+        $this->expectExceptionMessage("Workbook already contains a worksheet named 'someSheet2'. Rename this worksheet first.");
         $sheet = new Worksheet();
         $sheet->setTitle('someSheet2');
         $spreadsheet->addSheet($sheet);
     }
 
+    public function testAddSheetDuplicateTitleWithDifferentCase(): void
+    {
+        $spreadsheet = $this->getSpreadsheet();
+        $this->expectException(Exception::class);
+        $this->expectExceptionMessage("Workbook already contains a worksheet named 'SomeSheet2'. Rename this worksheet first.");
+        $sheet = new Worksheet();
+        $sheet->setTitle('SomeSheet2');
+        $spreadsheet->addSheet($sheet);
+    }
+
     public function testAddSheetNoAdjustActive(): void
     {
         $spreadsheet = $this->getSpreadsheet();
@@ -101,6 +112,7 @@ public function testRemoveSheetIndexTooHigh(): void
     {
         $spreadsheet = $this->getSpreadsheet();
         $this->expectException(Exception::class);
+        $this->expectExceptionMessage('You tried to remove a sheet by the out of bounds index: 4. The actual number of sheets is 3.');
         $spreadsheet->removeSheetByIndex(4);
     }
 
@@ -126,6 +138,7 @@ public function testGetSheetIndexTooHigh(): void
     {
         $spreadsheet = $this->getSpreadsheet();
         $this->expectException(Exception::class);
+        $this->expectExceptionMessage('Your requested sheet index: 4 is out of bounds. The actual number of sheets is 3.');
         $spreadsheet->getSheet(4);
     }
 
@@ -133,6 +146,7 @@ public function testGetIndexNonExistent(): void
     {
         $spreadsheet = $this->getSpreadsheet();
         $this->expectException(Exception::class);
+        $this->expectExceptionMessage('Sheet does not exist.');
         $sheet = new Worksheet();
         $sheet->setTitle('someSheet4');
         $spreadsheet->getIndex($sheet);
@@ -178,6 +192,7 @@ public function testSetActiveSheetIndexTooHigh(): void
     {
         $spreadsheet = $this->getSpreadsheet();
         $this->expectException(Exception::class);
+        $this->expectExceptionMessage('You tried to set a sheet active by the out of bounds index: 4. The actual number of sheets is 3.');
         $spreadsheet->setActiveSheetIndex(4);
     }
 
@@ -185,6 +200,7 @@ public function testSetActiveSheetNoSuchName(): void
     {
         $spreadsheet = $this->getSpreadsheet();
         $this->expectException(Exception::class);
+        $this->expectExceptionMessage('Workbook does not contain sheet:unknown');
         $spreadsheet->setActiveSheetIndexByName('unknown');
     }
 
@@ -213,6 +229,7 @@ public function testAddExternal(): void
     public function testAddExternalDuplicateName(): void
     {
         $this->expectException(Exception::class);
+        $this->expectExceptionMessage("Workbook already contains a worksheet named 'someSheet1'. Rename the external sheet first.");
         $spreadsheet = new Spreadsheet();
         $sheet = $spreadsheet->createSheet()->setTitle('someSheet1');
         $sheet->getCell('A1')->setValue(1);