diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index 6c5cde1f..22e6a3cc 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -1098,6 +1098,14 @@ Prolog:
   extensions:
   - .pro
 
+Protocol Buffer:
+  type: markup
+  ace_mode: protobuf
+  aliases:
+  - protobuf
+  - Protocol Buffers
+  primary_extension: .proto
+
 Puppet:
   type: programming
   color: "#cc5555"
diff --git a/samples/Protocol Buffer/addressbook.proto b/samples/Protocol Buffer/addressbook.proto
new file mode 100644
index 00000000..2dee2965
--- /dev/null
+++ b/samples/Protocol Buffer/addressbook.proto	
@@ -0,0 +1,27 @@
+package tutorial;
+
+option java_package = "com.example.tutorial";
+option java_outer_classname = "AddressBookProtos";
+
+message Person {
+  required string name = 1;
+  required int32 id = 2;
+  optional string email = 3;
+
+  enum PhoneType {
+    MOBILE = 0;
+    HOME = 1;
+    WORK = 2;
+  }
+
+  message PhoneNumber {
+    required string number = 1;
+    optional PhoneType type = 2 [default = HOME];
+  }
+
+  repeated PhoneNumber phone = 4;
+}
+
+message AddressBook {
+  repeated Person person = 1;
+}