diff --git a/lib/BlockingDriver.php b/lib/BlockingDriver.php
index d5de5e6..7adc9f7 100644
--- a/lib/BlockingDriver.php
+++ b/lib/BlockingDriver.php
@@ -262,7 +262,7 @@ class BlockingDriver implements Driver {
     /**
      * {@inheritdoc}
      */
-    public function mkdir(string $path, int $mode = 0644, bool $recursive = false): Promise {
+    public function mkdir(string $path, int $mode = 0777, bool $recursive = false): Promise {
         return new Success((bool) @\mkdir($path, $mode, $recursive));
     }
 
diff --git a/lib/Driver.php b/lib/Driver.php
index dfc0623..0060aef 100644
--- a/lib/Driver.php
+++ b/lib/Driver.php
@@ -151,7 +151,7 @@ interface Driver {
      * @param bool $recursive
      * @return \Amp\Promise
      */
-    public function mkdir(string $path, int $mode = 0644, bool $recursive = false): Promise;
+    public function mkdir(string $path, int $mode = 0777, bool $recursive = false): Promise;
 
     /**
      * Delete a directory.
diff --git a/lib/EioDriver.php b/lib/EioDriver.php
index ce95ee8..e3e6d3f 100644
--- a/lib/EioDriver.php
+++ b/lib/EioDriver.php
@@ -349,7 +349,7 @@ class EioDriver implements Driver {
     /**
      * {@inheritdoc}
      */
-    public function mkdir(string $path, int $mode = 0644, bool $recursive = false): Promise {
+    public function mkdir(string $path, int $mode = 0777, bool $recursive = false): Promise {
         $deferred = new Deferred;
         $this->poll->listen($deferred->promise());
 
diff --git a/lib/ParallelDriver.php b/lib/ParallelDriver.php
index 0d44924..b69b275 100644
--- a/lib/ParallelDriver.php
+++ b/lib/ParallelDriver.php
@@ -142,7 +142,7 @@ class ParallelDriver implements Driver {
     /**
      * {@inheritdoc}
      */
-    public function mkdir(string $path, int $mode = 0644, bool $recursive = false): Promise {
+    public function mkdir(string $path, int $mode = 0777, bool $recursive = false): Promise {
         return new Coroutine($this->runFileTask(new Internal\FileTask("mkdir", [$path, $mode, $recursive])));
     }
 
diff --git a/lib/UvDriver.php b/lib/UvDriver.php
index 13920a5..af698c2 100644
--- a/lib/UvDriver.php
+++ b/lib/UvDriver.php
@@ -352,7 +352,7 @@ class UvDriver implements Driver {
     /**
      * {@inheritdoc}
      */
-    public function mkdir(string $path, int $mode = 0644, bool $recursive = false): Promise {
+    public function mkdir(string $path, int $mode = 0777, bool $recursive = false): Promise {
         $deferred = new Deferred;
         $this->poll->listen($deferred->promise());