diff --git a/CHANGELOG.md b/CHANGELOG.md
index deca8bce..cb802792 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 ## v3.25.0
 - Add ForeachUseValueFixer
 - Add NoUselessWriteVisibilityFixer
+- Add TrimKeyFixer
 - ReadonlyPromotedPropertiesFixer - support asymmetric visibility
 
 ## v3.24.0
diff --git a/README.md b/README.md
index 08ce7ba8..ec461e0a 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@
 [![Latest stable version](https://img.shields.io/packagist/v/kubawerlos/php-cs-fixer-custom-fixers.svg?label=current%20version)](https://packagist.org/packages/kubawerlos/php-cs-fixer-custom-fixers)
 [![PHP version](https://img.shields.io/packagist/php-v/kubawerlos/php-cs-fixer-custom-fixers.svg)](https://php.net)
 [![License](https://img.shields.io/github/license/kubawerlos/php-cs-fixer-custom-fixers.svg)](LICENSE)
-![Tests](https://img.shields.io/badge/tests-3666-brightgreen.svg)
+![Tests](https://img.shields.io/badge/tests-3691-brightgreen.svg)
 [![Downloads](https://img.shields.io/packagist/dt/kubawerlos/php-cs-fixer-custom-fixers.svg)](https://packagist.org/packages/kubawerlos/php-cs-fixer-custom-fixers)
 
 [![CI status](https://github.com/kubawerlos/php-cs-fixer-custom-fixers/actions/workflows/ci.yaml/badge.svg)](https://github.com/kubawerlos/php-cs-fixer-custom-fixers/actions/workflows/ci.yaml)
@@ -712,6 +712,18 @@ A class that implements the `__toString()` method must explicitly implement the
  }
 ```
 
+#### TrimKeyFixer
+A string array and yield keys must be trimmed and have no double spaces.
+```diff
+ <?php
+ $array = [
+-    'option 1 ' => 'v1',
+-    'option 2  or 3' => 'v23',
++    'option 1' => 'v1',
++    'option 2 or 3' => 'v23',
+ ];
+```
+
 
 ## Contributing
 Request a feature or report a bug by creating an [issue](https://github.com/kubawerlos/php-cs-fixer-custom-fixers/issues).
diff --git a/src/Fixer/TrimKeyFixer.php b/src/Fixer/TrimKeyFixer.php
new file mode 100644
index 00000000..f90a7c9e
--- /dev/null
+++ b/src/Fixer/TrimKeyFixer.php
@@ -0,0 +1,96 @@
+<?php declare(strict_types=1);
+
+/*
+ * This file is part of PHP CS Fixer: custom fixers.
+ *
+ * (c) 2018 Kuba Werłos
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace PhpCsFixerCustomFixers\Fixer;
+
+use PhpCsFixer\FixerDefinition\CodeSample;
+use PhpCsFixer\FixerDefinition\FixerDefinition;
+use PhpCsFixer\FixerDefinition\FixerDefinitionInterface;
+use PhpCsFixer\Preg;
+use PhpCsFixer\Tokenizer\Token;
+use PhpCsFixer\Tokenizer\Tokens;
+
+final class TrimKeyFixer extends AbstractFixer
+{
+    public function getDefinition(): FixerDefinitionInterface
+    {
+        return new FixerDefinition(
+            'A string array and yield keys must be trimmed and have no double spaces.',
+            [new CodeSample(<<<'PHP'
+                <?php
+                $array = [
+                    'option 1 ' => 'v1',
+                    'option 2  or 3' => 'v23',
+                ];
+
+                PHP)],
+        );
+    }
+
+    public function getPriority(): int
+    {
+        return 0;
+    }
+
+    public function isCandidate(Tokens $tokens): bool
+    {
+        return $tokens->isAnyTokenKindsFound([\T_CONSTANT_ENCAPSED_STRING]);
+    }
+
+    public function isRisky(): bool
+    {
+        return false;
+    }
+
+    public function fix(\SplFileInfo $file, Tokens $tokens): void
+    {
+        for ($index = $tokens->count() - 1; $index > 0; $index--) {
+            if (!$tokens[$index]->isGivenKind(\T_DOUBLE_ARROW)) {
+                continue;
+            }
+
+            $indexToFix = $tokens->getPrevMeaningfulToken($index);
+            \assert(\is_int($indexToFix));
+
+            if (!$tokens[$indexToFix]->isGivenKind([\T_CONSTANT_ENCAPSED_STRING])) {
+                continue;
+            }
+
+            $content = $tokens[$indexToFix]->getContent();
+            $stringBorderQuote = $content[0];
+            $innerContent = \substr($content, 1, -1);
+
+            $newInnerContent = Preg::replace('/\\s{2,}/', ' ', $innerContent);
+
+            $prevIndex = $tokens->getPrevMeaningfulToken($indexToFix);
+            if (!$tokens[$prevIndex]->equals('.')) {
+                $newInnerContent = \ltrim($newInnerContent);
+            }
+
+            $nextIndex = $tokens->getNextMeaningfulToken($indexToFix);
+            if (!$tokens[$nextIndex]->equals('.')) {
+                $newInnerContent = \rtrim($newInnerContent);
+            }
+
+            if ($newInnerContent === '') {
+                continue;
+            }
+
+            $newContent = $stringBorderQuote . $newInnerContent . $stringBorderQuote;
+
+            if ($content === $newContent) {
+                continue;
+            }
+
+            $tokens[$indexToFix] = new Token([\T_CONSTANT_ENCAPSED_STRING, $newContent]);
+        }
+    }
+}
diff --git a/tests/Fixer/TrimKeyFixerTest.php b/tests/Fixer/TrimKeyFixerTest.php
new file mode 100644
index 00000000..a16f10e5
--- /dev/null
+++ b/tests/Fixer/TrimKeyFixerTest.php
@@ -0,0 +1,113 @@
+<?php declare(strict_types=1);
+
+/*
+ * This file is part of PHP CS Fixer: custom fixers.
+ *
+ * (c) 2018 Kuba Werłos
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace Tests\Fixer;
+
+/**
+ * @internal
+ *
+ * @covers \PhpCsFixerCustomFixers\Fixer\TrimKeyFixer
+ */
+final class TrimKeyFixerTest extends AbstractFixerTestCase
+{
+    public function testIsRisky(): void
+    {
+        self::assertRiskiness(false);
+    }
+
+    /**
+     * @dataProvider provideFixCases
+     */
+    public function testFix(string $expected, ?string $input = null): void
+    {
+        $this->doTest($expected, $input);
+    }
+
+    /**
+     * @return iterable<array{0: string, 1?: string}>
+     */
+    public static function provideFixCases(): iterable
+    {
+        yield 'do not trim when with concatenation' => [
+            <<<'PHP'
+                <?php return [
+                    'foo '. $a => 'v',
+                    $b . ' foo' => 'v',
+                    $c . ' foo ' . $d => 'v',
+                ];
+                PHP,
+        ];
+
+        yield 'trim array' => [
+            <<<'PHP'
+                <?php return [
+                    'k1' => 'v ',
+                    "k2" => "v",
+                    'k3' => ' v',
+                    "k4" => "v",
+                    'k5' => 'v',
+                ];
+                PHP,
+            <<<'PHP'
+                <?php return [
+                    'k1 ' => 'v ',
+                    "k2    " => "v",
+                    ' k3' => ' v',
+                    "    k4" => "v",
+                    '    k5    ' => 'v',
+                ];
+                PHP,
+        ];
+
+        yield 'trim generator' => [
+            <<<'PHP'
+                <?php function g() {
+                    yield 'k1' => 'v';
+                    yield 'k2' => 'v';
+                    yield 'k3' => ' v ';
+                    yield 'k4' => 'v';
+                    yield 'k5' => 'v';
+                    yield 'k6' => 'v';
+                }
+                PHP,
+            <<<'PHP'
+                <?php function g() {
+                    yield 'k1 ' => 'v';
+                    yield 'k2    ' => 'v';
+                    yield 'k3' => ' v ';
+                    yield ' k4' => 'v';
+                    yield '    k5' => 'v';
+                    yield '    k6    ' => 'v';
+                }
+                PHP,
+        ];
+        yield 'trim strings having non-whitespace characters' => [
+            <<<'PHP'
+                <?php return [
+                    'k1' => true,
+                    0 => 0,
+                    ' ' => 1,
+                    '  ' => 2,
+                    'k2' => false,
+                ];
+                PHP,
+            <<<'PHP'
+                <?php return [
+                    ' k1 ' => true,
+                    0 => 0,
+                    ' ' => 1,
+                    '  ' => 2,
+                    ' k2 ' => false,
+                ];
+                PHP,
+        ];
+    }
+}