diff --git a/src/Cli.php b/src/Cli.php
index 4cb359d..dfca919 100644
--- a/src/Cli.php
+++ b/src/Cli.php
@@ -30,6 +30,8 @@ class Cli
 
     public const PARAMETER_ONLY = 'only';
 
+    public const PARAMETER_MEMORY_LIMIT = 'memory-limit';
+
     public static function isOnWindows(): bool
     {
         return PHP_OS_FAMILY === 'Windows';
diff --git a/src/Commands/RunCommand.php b/src/Commands/RunCommand.php
index 28c02f0..c734484 100644
--- a/src/Commands/RunCommand.php
+++ b/src/Commands/RunCommand.php
@@ -107,6 +107,13 @@ protected function configure(): void
             'Only returns with exit code 0, regardless of any errors/warnings'
         );
 
+        $this->addOption(
+            Cli::PARAMETER_MEMORY_LIMIT,
+            'm',
+            InputOption::VALUE_REQUIRED,
+            'Sets the PHP memory limit for child processes (e.g. "512M", "-1" for unlimited)'
+        );
+
         $this->addArgument(
             'files',
             InputArgument::IS_ARRAY | InputArgument::OPTIONAL,
@@ -129,6 +136,7 @@ protected function execute(InputInterface $input, OutputInterface $output): int
         $context->isFixing = (bool) $input->getOption(Cli::FLAG_FIX) || $this->config->shouldAutoFix();
         $context->runningInCi = (bool) $input->getOption(Cli::FLAG_CI);
         $context->files = $files;
+        $context->memoryLimit = $input->getOption(Cli::PARAMETER_MEMORY_LIMIT);
 
         if ($context->runningInCi) {
             $input->setInteractive(false);
@@ -185,6 +193,7 @@ private function executeContext(InputInterface $input, OutputInterface $output,
 
             $tool->setInput($input);
             $tool->setOutput($output);
+            $tool->setContext($context);
 
             $start = time();
             $result = $tool->run($context);
diff --git a/src/Context.php b/src/Context.php
index 1790b42..ae576f7 100644
--- a/src/Context.php
+++ b/src/Context.php
@@ -26,6 +26,9 @@ class Context
     /** @var string[] */
     public $toolsExecuted = [];
 
+    /** @var string|null */
+    public $memoryLimit = null;
+
     /** @var Result */
     public $result;
 
diff --git a/src/Tools/ComposerNormalize.php b/src/Tools/ComposerNormalize.php
index bd19987..4600409 100644
--- a/src/Tools/ComposerNormalize.php
+++ b/src/Tools/ComposerNormalize.php
@@ -24,6 +24,11 @@ class ComposerNormalize extends Tool
     /** @var string */
     protected $name = 'composer-normalize';
 
+    protected function supportsMemoryLimit(): bool
+    {
+        return false;
+    }
+
     public function shouldRun(Context $context): bool
     {
         // TODO does not check against file names, only full paths
diff --git a/src/Tools/Deptrac.php b/src/Tools/Deptrac.php
index 83a3b32..8638d3d 100644
--- a/src/Tools/Deptrac.php
+++ b/src/Tools/Deptrac.php
@@ -16,6 +16,11 @@ class Deptrac extends Tool
     /** @var string */
     protected $name = 'deptrac';
 
+    protected function supportsMemoryLimit(): bool
+    {
+        return true;
+    }
+
     public function run(Context $context): bool
     {
         $outputFile = $this->createTempReportFile();
diff --git a/src/Tools/EasyCodingStandard.php b/src/Tools/EasyCodingStandard.php
index 1782d39..75da122 100644
--- a/src/Tools/EasyCodingStandard.php
+++ b/src/Tools/EasyCodingStandard.php
@@ -24,6 +24,11 @@ class EasyCodingStandard extends Tool
     /** @var string */
     protected $name = 'ecs';
 
+    protected function supportsMemoryLimit(): bool
+    {
+        return true;
+    }
+
     public function run(Context $context): bool
     {
         $output = [];
diff --git a/src/Tools/Phan.php b/src/Tools/Phan.php
index 4b5f128..4fc8af8 100644
--- a/src/Tools/Phan.php
+++ b/src/Tools/Phan.php
@@ -16,6 +16,11 @@ class Phan extends Tool
     /** @var string */
     protected $name = 'phan';
 
+    protected function supportsMemoryLimit(): bool
+    {
+        return true;
+    }
+
     public function run(Context $context): bool
     {
         $outputFile = $this->createTempReportFile();
diff --git a/src/Tools/PhpCodeSniffer.php b/src/Tools/PhpCodeSniffer.php
index 0ef63eb..eb01604 100644
--- a/src/Tools/PhpCodeSniffer.php
+++ b/src/Tools/PhpCodeSniffer.php
@@ -14,6 +14,11 @@ class PhpCodeSniffer extends Tool
     /** @var string */
     protected $name = 'php_codesniffer';
 
+    protected function supportsMemoryLimit(): bool
+    {
+        return true;
+    }
+
     public function run(Context $context): bool
     {
         if ($context->isFixing) {
diff --git a/src/Tools/PhpMessDetector.php b/src/Tools/PhpMessDetector.php
index 6474d1a..24e96ad 100644
--- a/src/Tools/PhpMessDetector.php
+++ b/src/Tools/PhpMessDetector.php
@@ -14,6 +14,11 @@ class PhpMessDetector extends Tool
     /** @var string */
     protected $name = 'phpmd';
 
+    protected function supportsMemoryLimit(): bool
+    {
+        return true;
+    }
+
     public function run(Context $context): bool
     {
         $output = [];
diff --git a/src/Tools/PhpParallelLint/PhpParallelLint.php b/src/Tools/PhpParallelLint/PhpParallelLint.php
index 9890fbe..4803b56 100644
--- a/src/Tools/PhpParallelLint/PhpParallelLint.php
+++ b/src/Tools/PhpParallelLint/PhpParallelLint.php
@@ -15,6 +15,11 @@ class PhpParallelLint extends Tool
     /** @var string */
     protected $name = self::NAME;
 
+    protected function supportsMemoryLimit(): bool
+    {
+        return true;
+    }
+
     public function run(Context $context): bool
     {
         $config = $context->config->getPart($this->name);
diff --git a/src/Tools/Phpstan.php b/src/Tools/Phpstan.php
index f2ac2dc..0581bdc 100644
--- a/src/Tools/Phpstan.php
+++ b/src/Tools/Phpstan.php
@@ -17,6 +17,11 @@ class Phpstan extends Tool
     /** @var string */
     protected $name = 'phpstan';
 
+    protected function supportsMemoryLimit(): bool
+    {
+        return true;
+    }
+
     public function run(Context $context): bool
     {
         $ignoreSources = (bool) ($context->config->getPart($this->getName())[Config::IGNORE_SOURCES] ?? false);
diff --git a/src/Tools/Psalm.php b/src/Tools/Psalm.php
index 72c454d..6f81b65 100644
--- a/src/Tools/Psalm.php
+++ b/src/Tools/Psalm.php
@@ -20,6 +20,11 @@ class Psalm extends Tool
     /** @var string */
     protected $name = 'psalm';
 
+    protected function supportsMemoryLimit(): bool
+    {
+        return true;
+    }
+
     public function run(Context $context): bool
     {
         $binary = self::vendorBinary($this->name);
diff --git a/src/Tools/Rector.php b/src/Tools/Rector.php
index 7c50e84..c2bea4b 100644
--- a/src/Tools/Rector.php
+++ b/src/Tools/Rector.php
@@ -21,6 +21,11 @@ class Rector extends Tool
     /** @var string */
     protected $name = 'rector';
 
+    protected function supportsMemoryLimit(): bool
+    {
+        return true;
+    }
+
     public function run(Context $context): bool
     {
         $binary = self::vendorBinary('rector');
diff --git a/src/Tools/Tool.php b/src/Tools/Tool.php
index 58e6e87..305081e 100644
--- a/src/Tools/Tool.php
+++ b/src/Tools/Tool.php
@@ -35,6 +35,9 @@ abstract class Tool
     /** @var OutputInterface */
     protected $output;
 
+    /** @var Context|null */
+    protected $context;
+
     public function setInput(InputInterface $input): void
     {
         $this->input = $input;
@@ -45,6 +48,11 @@ public function setOutput(OutputInterface $output): void
         $this->output = $output;
     }
 
+    public function setContext(Context $context): void
+    {
+        $this->context = $context;
+    }
+
     /**
      * Runs this tool with the given context.
      */
@@ -84,7 +92,13 @@ protected function execute(
             return $argument !== '';
         });
 
-        $command = array_merge([$binary], $arguments);
+        $memoryLimit = $this->context !== null ? $this->context->memoryLimit : null;
+
+        if ($memoryLimit !== null && $this->supportsMemoryLimit()) {
+            $command = array_merge([PHP_BINARY, '-d', "memory_limit={$memoryLimit}", $binary], $arguments);
+        } else {
+            $command = array_merge([$binary], $arguments);
+        }
 
         if ($this->output->isVeryVerbose()) {
             $this->output->writeln('Executing: ' . implode(' ', $command), Output::OUTPUT_RAW);
@@ -129,6 +143,8 @@ protected function execute(
         return (int) $process->getExitCode();
     }
 
+    abstract protected function supportsMemoryLimit(): bool;
+
     protected static function vendorBinary(string $binary): string
     {
         $binary = PHPCSTD_BINARY_PATH . $binary;