diff --git a/data/core/commands/core.lua b/data/core/commands/core.lua
index e8ed61b..8843a75 100644
--- a/data/core/commands/core.lua
+++ b/data/core/commands/core.lua
@@ -7,6 +7,8 @@ local DocView = require "core.docview"
 local LogView = require "core.logview"
 
 
+local fullscreen = false
+
 command.add(nil, {
   ["core:quit"] = function()
     core.quit()
@@ -16,6 +18,11 @@ command.add(nil, {
     core.quit(true)
   end,
 
+  ["core:toggle-fullscreen"] = function()
+    fullscreen = not fullscreen
+    system.set_fullscreen(fullscreen)
+  end,
+
   ["core:reload-module"] = function()
     core.command_view:enter("Reload Module", function(text, item)
       local text = item and item.text or text
diff --git a/data/core/keymap.lua b/data/core/keymap.lua
index fe2e45e..e506d24 100644
--- a/data/core/keymap.lua
+++ b/data/core/keymap.lua
@@ -88,6 +88,7 @@ keymap.add {
   ["ctrl+p"] = "core:open-project-file",
   ["ctrl+o"] = "core:open-file",
   ["ctrl+n"] = "core:new-doc",
+  ["alt+return"] = "core:toggle-fullscreen",
 
   ["alt+shift+j"] = "root:split-left",
   ["alt+shift+l"] = "root:split-right",
diff --git a/src/api/system.c b/src/api/system.c
index 675c379..cd18376 100644
--- a/src/api/system.c
+++ b/src/api/system.c
@@ -1,6 +1,7 @@
 #include <SDL2/SDL.h>
 #include <ctype.h>
 #include <dirent.h>
+#include <stdbool.h>
 #include <sys/stat.h>
 #include "api.h"
 #ifdef _WIN32
@@ -160,6 +161,14 @@ static int f_set_window_title(lua_State *L) {
 }
 
 
+static int f_set_fullscreen(lua_State *L) {
+  luaL_checkany(L, 1);
+  bool b = lua_toboolean(L, 1);
+  SDL_SetWindowFullscreen(window, b ? SDL_WINDOW_FULLSCREEN_DESKTOP : 0);
+  return 0;
+}
+
+
 static int f_window_has_focus(lua_State *L) {
   unsigned flags = SDL_GetWindowFlags(window);
   lua_pushboolean(L, flags & SDL_WINDOW_INPUT_FOCUS);
@@ -318,6 +327,7 @@ static const luaL_Reg lib[] = {
   { "poll_event",          f_poll_event          },
   { "set_cursor",          f_set_cursor          },
   { "set_window_title",    f_set_window_title    },
+  { "set_fullscreen",      f_set_fullscreen      },
   { "window_has_focus",    f_window_has_focus    },
   { "show_confirm_dialog", f_show_confirm_dialog },
   { "list_dir",            f_list_dir            },