diff --git a/binding-mri/oneshot-binding.cpp b/binding-mri/oneshot-binding.cpp
index b933a36..fc253a6 100644
--- a/binding-mri/oneshot-binding.cpp
+++ b/binding-mri/oneshot-binding.cpp
@@ -107,6 +107,7 @@ void oneshotBindingInit()
 	VALUE msg = rb_define_module_under(module, "Msg");
 
 	// Constants
+	rb_const_set(module, rb_intern("OS"), rb_str_new2(shState->oneshot().os().c_str()));
 	rb_const_set(module, rb_intern("USER_NAME"), rb_str_new2(shState->oneshot().userName().c_str()));
 	rb_const_set(module, rb_intern("SAVE_PATH"), rb_str_new2(shState->oneshot().savePath().c_str()));
 	rb_const_set(module, rb_intern("DOCS_PATH"), rb_str_new2(shState->oneshot().docsPath().c_str()));
diff --git a/src/oneshot.cpp b/src/oneshot.cpp
index 98c350f..01e56fd 100644
--- a/src/oneshot.cpp
+++ b/src/oneshot.cpp
@@ -49,6 +49,7 @@ struct OneshotPrivate
 	SDL_Window *window;
 
 	// String data
+	std::string os;
 	std::string lang;
 	std::string userName;
 	std::string savePath;
@@ -183,6 +184,13 @@ Oneshot::Oneshot(RGSSThreadData &threadData) :
 	p->winPosChanged = false;
 	p->allowExit = true;
 	p->exiting = false;
+	#ifdef OS_W32
+		p->os = "windows";
+	#elif defined OS_OSX
+		p->os = "macos";
+	#else
+		p->os = "linux";
+	#endif
 
 	/********************
 	 * USERNAME/DOCS PATH
@@ -373,6 +381,11 @@ void Oneshot::update()
 	}
 }
 
+const std::string &Oneshot::os() const
+{
+	return p->os;
+}
+
 const std::string &Oneshot::lang() const
 {
 	return p->lang;
diff --git a/src/oneshot.h b/src/oneshot.h
index bc40a9a..bb02091 100644
--- a/src/oneshot.h
+++ b/src/oneshot.h
@@ -49,6 +49,7 @@ public:
 	void update();
 
 	//Accessors
+	const std::string &os() const;
 	const std::string &lang() const;
 	const std::string &userName() const;
 	const std::string &savePath() const;