diff --git a/src/Mutator/Unwrap/UnwrapLcFirst.php b/src/Mutator/Unwrap/UnwrapLcFirst.php
new file mode 100644
index 000000000..4a8cf6eab
--- /dev/null
+++ b/src/Mutator/Unwrap/UnwrapLcFirst.php
@@ -0,0 +1,54 @@
+<?php
+/**
+ * This code is licensed under the BSD 3-Clause License.
+ *
+ * Copyright (c) 2017-2019, Maks Rafalko
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ *   list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ *   this list of conditions and the following disclaimer in the documentation
+ *   and/or other materials provided with the distribution.
+ *
+ * * Neither the name of the copyright holder nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+declare(strict_types=1);
+
+namespace Infection\Mutator\Unwrap;
+
+use PhpParser\Node;
+
+/**
+ * @internal
+ */
+final class UnwrapLcFirst extends AbstractUnwrapMutator
+{
+    protected function getFunctionName(): string
+    {
+        return 'lcfirst';
+    }
+
+    protected function getParameterIndexes(Node $node): \Generator
+    {
+        yield 0;
+    }
+}
diff --git a/src/Mutator/Util/MutatorProfile.php b/src/Mutator/Util/MutatorProfile.php
index aadb367a5..a97ca4cab 100644
--- a/src/Mutator/Util/MutatorProfile.php
+++ b/src/Mutator/Util/MutatorProfile.php
@@ -221,6 +221,7 @@ final class MutatorProfile
         Mutator\Unwrap\UnwrapArrayUintersectUassoc::class,
         Mutator\Unwrap\UnwrapArrayUnique::class,
         Mutator\Unwrap\UnwrapArrayValues::class,
+        Mutator\Unwrap\UnwrapLcFirst::class,
         Mutator\Unwrap\UnwrapStrRepeat::class,
         Mutator\Unwrap\UnwrapStrToLower::class,
         Mutator\Unwrap\UnwrapStrToUpper::class,
@@ -382,6 +383,7 @@ final class MutatorProfile
         'UnwrapArrayUintersectUassoc' => Mutator\Unwrap\UnwrapArrayUintersectUassoc::class,
         'UnwrapArrayUnique' => Mutator\Unwrap\UnwrapArrayUnique::class,
         'UnwrapArrayValues' => Mutator\Unwrap\UnwrapArrayValues::class,
+        'UnwrapLcFirst' => Mutator\Unwrap\UnwrapLcFirst::class,
         'UnwrapStrRepeat' => Mutator\Unwrap\UnwrapStrRepeat::class,
         'UnwrapStrToLower' => Mutator\Unwrap\UnwrapStrToLower::class,
         'UnwrapStrToUpper' => Mutator\Unwrap\UnwrapStrToUpper::class,
diff --git a/tests/Mutator/Unwrap/UnwrapLcFirstTest.php b/tests/Mutator/Unwrap/UnwrapLcFirstTest.php
new file mode 100644
index 000000000..953dc10ac
--- /dev/null
+++ b/tests/Mutator/Unwrap/UnwrapLcFirstTest.php
@@ -0,0 +1,184 @@
+<?php
+/**
+ * This code is licensed under the BSD 3-Clause License.
+ *
+ * Copyright (c) 2017-2019, Maks Rafalko
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ *   list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright notice,
+ *   this list of conditions and the following disclaimer in the documentation
+ *   and/or other materials provided with the distribution.
+ *
+ * * Neither the name of the copyright holder nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+declare(strict_types=1);
+
+namespace Infection\Tests\Mutator\Unwrap;
+
+use Infection\Tests\Mutator\AbstractMutatorTestCase;
+
+/**
+ * @internal
+ */
+final class UnwrapLcFirstTest extends AbstractMutatorTestCase
+{
+    /**
+     * @dataProvider provideMutationCases
+     */
+    public function test_mutator($input, $expected = null): void
+    {
+        $this->doTest($input, $expected);
+    }
+
+    public function provideMutationCases(): \Generator
+    {
+        yield 'It mutates correctly when provided with a string' => [
+            <<<'PHP'
+<?php
+
+$a = lcfirst('Good Afternoon!');
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = 'Good Afternoon!';
+PHP
+        ];
+
+        yield 'It mutates correctly when provided with a constant' => [
+            <<<'PHP'
+<?php
+
+$a = lcfirst(\Class_With_Const::Const);
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = \Class_With_Const::Const;
+PHP
+        ];
+
+        yield 'It mutates correctly when a backslash is in front of lcfirst' => [
+            <<<'PHP'
+<?php
+
+$a = \lcfirst('Good Afternoon!');
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = 'Good Afternoon!';
+PHP
+        ];
+
+        yield 'It mutates correctly within if statements' => [
+            <<<'PHP'
+<?php
+
+$a = 'Good Afternoon!';
+if (lcfirst($a) === $a) {
+    return true;
+}
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = 'Good Afternoon!';
+if ($a === $a) {
+    return true;
+}
+PHP
+        ];
+
+        yield 'It mutates correctly when lcfirst is wrongly capitalized' => [
+            <<<'PHP'
+<?php
+
+$a = lCfIrSt('Good Afternoon!');
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = 'Good Afternoon!';
+PHP
+        ];
+
+        yield 'It mutates correctly when lcfirst uses another function as input' => [
+            <<<'PHP'
+<?php
+
+$a = lcfirst($foo->bar());
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = $foo->bar();
+PHP
+        ];
+
+        yield 'It mutates correctly when provided with a more complex situation' => [
+            <<<'PHP'
+<?php
+
+$a = lcfirst(array_reduce($words, function (string $carry, string $item) {
+    return $carry . substr($item, 0, 1);
+}));
+PHP
+            ,
+            <<<'PHP'
+<?php
+
+$a = array_reduce($words, function (string $carry, string $item) {
+    return $carry . substr($item, 0, 1);
+});
+PHP
+        ];
+
+        yield 'It does not mutate functions named lcfirst' => [
+            <<<'PHP'
+<?php
+
+function lcfirst($string)
+{
+}
+PHP
+        ];
+
+        yield 'It does not break when provided with a variable function name' => [
+            <<<'PHP'
+<?php
+
+$a = 'lcfirst';
+
+$b = $a(' FooBar ');
+PHP
+            ,
+        ];
+    }
+}