diff --git a/src/Expectation.php b/src/Expectation.php
index 4f583004..fcfe88d5 100644
--- a/src/Expectation.php
+++ b/src/Expectation.php
@@ -753,7 +753,9 @@ final class Expectation
         }
 
         foreach ($this->value as $k => $item) {
-            $this->and($k)->toBeSnakeCase($message);
+            if (is_string($k)) {
+                $this->and($k)->toBeSnakeCase($message);
+            }
 
             if (is_array($item)) {
                 $this->and($item)->toHaveSnakeCaseKeys($message);
@@ -775,7 +777,9 @@ final class Expectation
         }
 
         foreach ($this->value as $k => $item) {
-            $this->and($k)->toBeKebabCase($message);
+            if (is_string($k)) {
+                $this->and($k)->toBeKebabCase($message);
+            }
 
             if (is_array($item)) {
                 $this->and($item)->toHaveKebabCaseKeys($message);
@@ -797,7 +801,9 @@ final class Expectation
         }
 
         foreach ($this->value as $k => $item) {
-            $this->and($k)->toBeCamelCase($message);
+            if (is_string($k)) {
+                $this->and($k)->toBeCamelCase($message);
+            }
 
             if (is_array($item)) {
                 $this->and($item)->toHaveCamelCaseKeys($message);
@@ -819,7 +825,9 @@ final class Expectation
         }
 
         foreach ($this->value as $k => $item) {
-            $this->and($k)->toBeStudlyCase($message);
+            if (is_string($k)) {
+                $this->and($k)->toBeStudlyCase($message);
+            }
 
             if (is_array($item)) {
                 $this->and($item)->toHaveStudlyCaseKeys($message);
diff --git a/tests/Features/Expect/toHaveCamelCaseKeys.php b/tests/Features/Expect/toHaveCamelCaseKeys.php
index 4fc73428..cf465a99 100644
--- a/tests/Features/Expect/toHaveCamelCaseKeys.php
+++ b/tests/Features/Expect/toHaveCamelCaseKeys.php
@@ -11,6 +11,11 @@ $array = [
             'camel' => true,
             'camelCase' => true,
         ],
+        'list' => [
+            'abc',
+            'def',
+            'ghi',
+        ],
     ],
 ];
 
diff --git a/tests/Features/Expect/toHaveKebabCaseKeys.php b/tests/Features/Expect/toHaveKebabCaseKeys.php
index cb16bc93..7dff565d 100644
--- a/tests/Features/Expect/toHaveKebabCaseKeys.php
+++ b/tests/Features/Expect/toHaveKebabCaseKeys.php
@@ -11,6 +11,11 @@ $array = [
             'kebab' => true,
             'kebab-case' => true,
         ],
+        'list' => [
+            'abc',
+            'def',
+            'ghi',
+        ],
     ],
 ];
 
diff --git a/tests/Features/Expect/toHaveSnakeCaseKeys.php b/tests/Features/Expect/toHaveSnakeCaseKeys.php
index 584a4b65..f43d91c4 100644
--- a/tests/Features/Expect/toHaveSnakeCaseKeys.php
+++ b/tests/Features/Expect/toHaveSnakeCaseKeys.php
@@ -11,6 +11,11 @@ $array = [
             'snake' => true,
             'snake_case' => true,
         ],
+        'list' => [
+            'abc',
+            'def',
+            'ghi',
+        ],
     ],
 ];
 
diff --git a/tests/Features/Expect/toHaveStudlyCaseKeys.php b/tests/Features/Expect/toHaveStudlyCaseKeys.php
index 71c0713a..caab167e 100644
--- a/tests/Features/Expect/toHaveStudlyCaseKeys.php
+++ b/tests/Features/Expect/toHaveStudlyCaseKeys.php
@@ -11,6 +11,11 @@ $array = [
             'Studly' => true,
             'StudlyCase' => true,
         ],
+        'List' => [
+            'abc',
+            'def',
+            'ghi',
+        ],
     ],
 ];