diff --git a/src/CommandProcessor.php b/src/CommandProcessor.php
index 83372b3..a7077bc 100644
--- a/src/CommandProcessor.php
+++ b/src/CommandProcessor.php
@@ -11,6 +11,7 @@ class CommandProcessor
 
 		/** @var bool */
 		private $isWindows;
+		protected $configs = [];
 
 
 		/**
@@ -32,6 +33,15 @@ public function __construct($mode = self::MODE_DETECT)
 			}
 		}
 
+		/**
+		 * Add a configuration parameter to the command.
+		 * @param string $name
+		 * @param mixed $value
+		 */
+		public function addConfig($name, $value)
+		{
+			$this->configs[] = [$name, $value];
+		}
 
 		/**
 		 * @param  string $app
@@ -43,6 +53,15 @@ public function process($app, array $args, array $env = NULL)
 		{
 			$cmd = [];
 
+			foreach ($this->configs as $config) {
+				list($name, $value) = $config;
+				if ($value == NULL) {
+					$cmd[] = "-c $name";
+				} else {
+					$cmd[] = "-c $name=" . $this->escapeArgument($value);
+				}
+			}
+
 			foreach ($args as $arg) {
 				if (is_array($arg)) {
 					foreach ($arg as $key => $value) {
diff --git a/src/Git.php b/src/Git.php
index 575c7c9..73e9894 100644
--- a/src/Git.php
+++ b/src/Git.php
@@ -14,6 +14,15 @@ public function  __construct(IRunner $runner = NULL)
 			$this->runner = $runner !== NULL ? $runner : new Runners\CliRunner;
 		}
 
+		/**
+		 * Add a configuration parameter to the command.
+		 * @param string $name
+		 * @param mixed $value
+		 */
+		public function addConfig($name, $value)
+		{
+			$this->runner->addConfig($name, $value);
+		}
 
 		/**
 		 * @param  string $directory
diff --git a/src/GitRepository.php b/src/GitRepository.php
index 2ef6f83..324f525 100644
--- a/src/GitRepository.php
+++ b/src/GitRepository.php
@@ -32,6 +32,15 @@ public function __construct($repository, IRunner $runner = NULL)
 			$this->runner = $runner !== NULL ? $runner : new Runners\CliRunner;
 		}
 
+		/**
+		 * Add a configuration parameter to the command.
+		 * @param string $name
+		 * @param mixed $value
+		 */
+		public function addConfig($name, $value)
+		{
+			$this->runner->addConfig($name, $value);
+		}
 
 		/**
 		 * @return string
diff --git a/src/IRunner.php b/src/IRunner.php
index 453ff68..f63cac9 100644
--- a/src/IRunner.php
+++ b/src/IRunner.php
@@ -5,6 +5,13 @@
 
 	interface IRunner
 	{
+		/**
+		 * Add a configuration parameter to the command.
+		 * @param string $name
+		 * @param mixed $value
+		 */
+		function addConfig($name, $value);
+
 		/**
 		 * @param  string $cwd
 		 * @param  array<mixed> $args
diff --git a/src/Runners/CliRunner.php b/src/Runners/CliRunner.php
index 0acacd7..64595f5 100644
--- a/src/Runners/CliRunner.php
+++ b/src/Runners/CliRunner.php
@@ -26,6 +26,15 @@ public function __construct($gitBinary = 'git')
 			$this->commandProcessor = new CommandProcessor;
 		}
 
+		/**
+		 * Add a configuration parameter to the command.
+		 * @param string $name
+		 * @param mixed $value
+		 */
+		public function addConfig($name, $value)
+		{
+			$this->commandProcessor->addConfig($name, $value);
+		}
 
 		/**
 		 * @return RunnerResult
diff --git a/src/Runners/MemoryRunner.php b/src/Runners/MemoryRunner.php
index 2a06d43..a3161ab 100644
--- a/src/Runners/MemoryRunner.php
+++ b/src/Runners/MemoryRunner.php
@@ -29,6 +29,15 @@ public function __construct($cwd)
 			$this->commandProcessor = new CommandProcessor;
 		}
 
+		/**
+		 * Add a configuration parameter to the command.
+		 * @param string $name
+		 * @param mixed $value
+		 */
+		public function addConfig($name, $value)
+		{
+			$this->commandProcessor->addConfig($name, $value);
+		}
 
 		/**
 		 * @param  array<mixed> $args
diff --git a/src/Runners/OldGitRunner.php b/src/Runners/OldGitRunner.php
index cb07136..4142a0d 100644
--- a/src/Runners/OldGitRunner.php
+++ b/src/Runners/OldGitRunner.php
@@ -16,6 +16,15 @@ public function __construct(IRunner $runner = NULL)
 			$this->runner = $runner !== NULL ? $runner : new CliRunner;
 		}
 
+		/**
+		 * Add a configuration parameter to the command.
+		 * @param string $name
+		 * @param mixed $value
+		 */
+		public function addConfig($name, $value)
+		{
+			$this->runner->addConfig($name, $value);
+		}
 
 		public function run($cwd, array $args, array $env = NULL)
 		{
diff --git a/tests/GitPhp/CommandProcessor.phpt b/tests/GitPhp/CommandProcessor.phpt
index 936c0a5..f10d797 100644
--- a/tests/GitPhp/CommandProcessor.phpt
+++ b/tests/GitPhp/CommandProcessor.phpt
@@ -101,3 +101,20 @@ test(function () {
 
 	}, InvalidArgumentException::class, "Invalid mode 'INVALID'.");
 });
+
+test(function () {
+	$processor = new CommandProcessor(CommandProcessor::MODE_NON_WINDOWS);
+	$processor->addConfig('core.sshCommand', "ssh -i '/path/to/private key file' -o StrictHostKeyChecking=no -o IdentitiesOnly=yes");
+	$processor->addConfig('test', NULL);
+
+	Assert::same(implode(' ', [
+		'git',
+		"-c core.sshCommand='ssh -i '\''/path/to/private key file'\'' -o StrictHostKeyChecking=no -o IdentitiesOnly=yes'",
+		'-c test',
+		'clone',
+		"'https://github.com/test/test.git'",
+		'test',
+	]), $processor->process('git', ['clone', 'https://github.com/test/test.git', 'test']));
+
+	print($processor->process('git', ['clone', 'https://github.com/test/test.git', 'test']));
+});
diff --git a/tests/libs/AssertRunner.php b/tests/libs/AssertRunner.php
index db7d1e2..65ba3fd 100644
--- a/tests/libs/AssertRunner.php
+++ b/tests/libs/AssertRunner.php
@@ -29,6 +29,15 @@ public function __construct($cwd)
 			$this->commandProcessor = new CommandProcessor;
 		}
 
+		/**
+		 * Add a configuration parameter to the command.
+		 * @param string $name
+		 * @param mixed $value
+		 */
+		public function addConfig($name, $value)
+		{
+			$this->commandProcessor->addConfig($name, $value);
+		}
 
 		/**
 		 * @param  mixed[] $expectedArgs