diff --git a/src/StringHelper.php b/src/StringHelper.php
index 35e41a8..c9d841a 100644
--- a/src/StringHelper.php
+++ b/src/StringHelper.php
@@ -623,14 +623,20 @@ public static function rtrim(string|array $string, string $pattern = self::DEFAU
      * Returns the portion of the string that lies between the first occurrence of the start string
      * and the last occurrence of the end string after that.
      *
+     * If the end string is not provided, it defaults to the value of the start string.
+     *
      * @param string $string The input string.
      * @param string $start The string marking the start of the portion to extract.
-     * @param string $end The string marking the end of the portion to extract.
+     * @param string|null $end The string marking the end of the portion to extract.
      * @return string|null The portion of the string between the first occurrence of
      * start and the last occurrence of end, or null if either start or end cannot be found.
      */
-    public static function findBetween(string $string, string $start, string $end): ?string
+    public static function findBetween(string $string, string $start, ?string $end = null): ?string
     {
+        if ($end === null) {
+            $end = $start;
+        }
+
         $startPos = mb_strpos($string, $start);
 
         if ($startPos === false) {
@@ -651,13 +657,19 @@ public static function findBetween(string $string, string $start, string $end):
      * Returns the portion of the string between the initial occurrence of the 'start' string
      * and the next occurrence of the 'end' string.
      *
+     *  If the end string is not provided, it defaults to the value of the start string.
+     *
      * @param string $string The input string.
      * @param string $start The string marking the beginning of the segment to extract.
-     * @param string $end The string marking the termination of the segment.
+     * @param string|null $end The string marking the termination of the segment.
      * @return string|null Extracted segment, or null if 'start' or 'end' is not present.
      */
-    public static function findBetweenFirst(string $string, string $start, string $end): ?string
+    public static function findBetweenFirst(string $string, string $start, ?string $end = null): ?string
     {
+        if ($end === null) {
+            $end = $start;
+        }
+
         $startPos = mb_strpos($string, $start);
 
         if ($startPos === false) {
@@ -678,13 +690,19 @@ public static function findBetweenFirst(string $string, string $start, string $e
      * Returns the portion of the string between the latest 'start' string
      * and the subsequent 'end' string.
      *
+     *  If the end string is not provided, it defaults to the value of the start string.
+     *
      * @param string $string The input string.
      * @param string $start The string marking the beginning of the segment to extract.
-     * @param string $end The string marking the termination of the segment.
+     * @param string|null $end The string marking the termination of the segment.
      * @return string|null Extracted segment, or null if 'start' or 'end' is not present.
      */
-    public static function findBetweenLast(string $string, string $start, string $end): ?string
+    public static function findBetweenLast(string $string, string $start, ?string $end = null): ?string
     {
+        if ($end === null) {
+            $end = $start;
+        }
+
         $endPos = mb_strrpos($string, $end);
 
         if ($endPos === false) {
diff --git a/tests/StringHelperTest.php b/tests/StringHelperTest.php
index 99ca7de..7895078 100644
--- a/tests/StringHelperTest.php
+++ b/tests/StringHelperTest.php
@@ -767,7 +767,7 @@ public function testInvalidTrimPattern(): void
     /**
      * @dataProvider dataProviderFindBetween
      */
-    public function testFindBetween(string $string, string $start, string $end, ?string $expectedResult): void
+    public function testFindBetween(string $string, string $start, ?string $end, ?string $expectedResult): void
     {
         $this->assertSame($expectedResult, StringHelper::findBetween($string, $start, $end));
     }
@@ -786,6 +786,7 @@ public function dataProviderFindBetween(): array
             ['start only', 'start', 'end', null], // start found but no end
             ['end only', 'start', 'end', null], // end found but no start
             ['a1a2a3a', 'a', 'a', '1a2a3'], // same start and end
+            ['a1a2a3a', 'a', null, '1a2a3'], // end is null
             ['spécial !@#$%^&*()', 'spé', '&*()', 'cial !@#$%^'],  // Special characters
             ['من صالح هاشمی هستم', 'من ', ' هستم', 'صالح هاشمی'], // other languages
         ];
@@ -794,7 +795,7 @@ public function dataProviderFindBetween(): array
     /**
      * @dataProvider dataProviderFindBetweenFirst
      */
-    public function testFindBetweenFirst(string $string, string $start, string $end, ?string $expectedResult): void
+    public function testFindBetweenFirst(string $string, string $start, ?string $end, ?string $expectedResult): void
     {
         $this->assertSame($expectedResult, StringHelper::findBetweenFirst($string, $start, $end));
     }
@@ -815,6 +816,7 @@ public function dataProviderFindBetweenFirst(): array
             ['start only', 'start', 'end', null], // start found but no end
             ['end only', 'start', 'end', null], // end found but no start
             ['a1a2a3a', 'a', 'a', '1'], // same start and end
+            ['a1a2a3a', 'a', null, '1'], // end is null
             ['spécial !@#$%^&*()', 'spé', '&*()', 'cial !@#$%^'],  // Special characters
             ['من صالح هاشمی هستم هستم', 'من ', ' هستم', 'صالح هاشمی'], // other languages
         ];
@@ -823,7 +825,7 @@ public function dataProviderFindBetweenFirst(): array
     /**
      * @dataProvider dataProviderFindBetweenLast
      */
-    public function testFindBetweenLast(string $string, string $start, string $end, ?string $expectedResult): void
+    public function testFindBetweenLast(string $string, string $start, ?string $end, ?string $expectedResult): void
     {
         $this->assertSame($expectedResult, StringHelper::findBetweenLast($string, $start, $end));
     }
@@ -844,6 +846,7 @@ public function dataProviderFindBetweenLast(): array
             ['start only', 'start', 'end', null], // start found but no end
             ['end only', 'start', 'end', null], // end found but no start
             ['a1a2a3a', 'a', 'a', '3'], // same start and end
+            ['a1a2a3a', 'a', null, '3'], // end is null
             ['spécial !@#$%^&*()', 'spé', '&*()', 'cial !@#$%^'],  // Special characters
             ['من صالح هاشمی هستم هستم', 'من ', ' هستم', 'صالح هاشمی هستم'], // other languages
         ];