diff --git a/gui/include/streamwindow.h b/gui/include/streamwindow.h
index 45d1e1b..ffe3524 100644
--- a/gui/include/streamwindow.h
+++ b/gui/include/streamwindow.h
@@ -38,6 +38,8 @@ class StreamWindow: public QMainWindow
 
 		AVOpenGLWidget *av_widget;
 
+		void Init(const StreamSessionConnectInfo &connect_info);
+
 	protected:
 		void keyPressEvent(QKeyEvent *event) override;
 		void keyReleaseEvent(QKeyEvent *event) override;
@@ -45,6 +47,7 @@ class StreamWindow: public QMainWindow
 
 	private slots:
 		void SessionQuit(ChiakiQuitReason reason, const QString &reason_str);
+		void ToggleFullscreen();
 };
 
 #endif // CHIAKI_GUI_STREAMWINDOW_H
diff --git a/gui/src/streamwindow.cpp b/gui/src/streamwindow.cpp
index 1dd0d20..b5959ea 100644
--- a/gui/src/streamwindow.cpp
+++ b/gui/src/streamwindow.cpp
@@ -22,6 +22,7 @@
 #include <QLabel>
 #include <QMessageBox>
 #include <QCoreApplication>
+#include <QAction>
 
 StreamWindow::StreamWindow(const StreamSessionConnectInfo &connect_info, QWidget *parent)
 	: QMainWindow(parent)
@@ -30,19 +31,7 @@ StreamWindow::StreamWindow(const StreamSessionConnectInfo &connect_info, QWidget
 	setWindowTitle(qApp->applicationName());
 	try
 	{
-		session = new StreamSession(connect_info, this);
-
-		connect(session, &StreamSession::SessionQuit, this, &StreamWindow::SessionQuit);
-
-		av_widget = new AVOpenGLWidget(session->GetVideoDecoder(), this);
-		setCentralWidget(av_widget);
-
-		grabKeyboard();
-
-		session->Start();
-
-		resize(connect_info.video_profile.width, connect_info.video_profile.height);
-		show();
+		Init(connect_info);
 	}
 	catch(const Exception &e)
 	{
@@ -59,6 +48,28 @@ StreamWindow::~StreamWindow()
 	delete av_widget;
 }
 
+void StreamWindow::Init(const StreamSessionConnectInfo &connect_info)
+{
+	session = new StreamSession(connect_info, this);
+
+	connect(session, &StreamSession::SessionQuit, this, &StreamWindow::SessionQuit);
+
+	av_widget = new AVOpenGLWidget(session->GetVideoDecoder(), this);
+	setCentralWidget(av_widget);
+
+	grabKeyboard();
+
+	session->Start();
+
+	auto fullscreen_action = new QAction(tr("Fullscreen"), this);
+	fullscreen_action->setShortcut(Qt::Key_F11);
+	addAction(fullscreen_action);
+	connect(fullscreen_action, &QAction::triggered, this, &StreamWindow::ToggleFullscreen);
+
+	resize(connect_info.video_profile.width, connect_info.video_profile.height);
+	show();
+}
+
 void StreamWindow::keyPressEvent(QKeyEvent *event)
 {
 	if(session)
@@ -87,3 +98,17 @@ void StreamWindow::SessionQuit(ChiakiQuitReason reason, const QString &reason_st
 	QMessageBox::critical(this, tr("Session has quit"), m);
 	close();
 }
+
+void StreamWindow::ToggleFullscreen()
+{
+	if(isFullScreen())
+	{
+		setCursor(Qt::ArrowCursor);
+		showNormal();
+	}
+	else
+	{
+		setCursor(Qt::BlankCursor);
+		showFullScreen();
+	}
+}
\ No newline at end of file