diff --git a/data/gsettings/com.github.birros.WebArchives.gschema.xml b/data/gsettings/com.github.birros.WebArchives.gschema.xml
index 0efd4b9..c2978a0 100644
--- a/data/gsettings/com.github.birros.WebArchives.gschema.xml
+++ b/data/gsettings/com.github.birros.WebArchives.gschema.xml
@@ -5,5 +5,15 @@
             <summary>Night mode</summary>
             <description>Night mode state</description>
         </key>
+        <key name="window-maximized" type="b">
+            <default>true</default>
+            <summary>Window maximized</summary>
+            <description>Window maximized state.</description>
+        </key>
+        <key name="window-size" type="(ii)">
+            <default>(768, 600)</default>
+            <summary>Window size</summary>
+            <description>Window size (width and height).</description>
+        </key>
     </schema>
 </schemalist>
\ No newline at end of file
diff --git a/src/app/application.vala b/src/app/application.vala
index 810496c..2301b1e 100644
--- a/src/app/application.vala
+++ b/src/app/application.vala
@@ -1,7 +1,13 @@
 public class WebArchives.Application : Gtk.Application {
+    private struct Size {
+        int width;
+        int height;
+    }
+
     private Context context;
     private Persistence persistence;
     private GLib.Settings settings;
+    private HashTable<Gtk.Window, Size?> sizes;
     private const OptionEntry [] option_entries = {
         {
             "version", 'v', 0,
@@ -20,6 +26,7 @@ public class WebArchives.Application : Gtk.Application {
             flags: ApplicationFlags.HANDLES_OPEN
         );
 
+        sizes = new HashTable<Gtk.Window, Size?> (direct_hash, direct_equal);
         add_main_option_entries (option_entries);
     }
 
@@ -65,6 +72,9 @@ public class WebArchives.Application : Gtk.Application {
         context.night_mode_state.active = settings.get_boolean ("night-mode");
         info ("server_url: %s\n", context.server.url);
 
+        window_added.connect (on_window_added);
+        window_removed.connect (on_window_removed);
+
         // styles
         string[] styles = {
             "ui/gtk/notebook/notebook.css",
@@ -85,10 +95,8 @@ public class WebArchives.Application : Gtk.Application {
     protected override void activate () {
         Context window_context = new Context.fork (context, Context.Layer.APP);
         Window window = new Window (this, window_context);
-        /**
-         * FIXME: better support of window size, maximize saving and restoring.
-         */
-        window.maximize ();
+
+        add_window (window);
     }
 
     private void on_night_mode () {
@@ -103,6 +111,47 @@ public class WebArchives.Application : Gtk.Application {
         );
     }
 
+    private void on_window_added (Gtk.Window window) {
+        int width, height;
+        settings.get ("window-size", "(ii)", out width, out height);
+        bool maximized = settings.get_boolean ("window-maximized");
+
+        window.resize (width, height);
+        if (maximized) {
+            window.maximize ();
+        }
+
+        window.configure_event.connect ((event) => {
+            return on_configure_event (event, window);
+        });
+    }
+
+    private bool on_configure_event (
+        Gdk.EventConfigure event, Gtk.Window window
+    ) {
+        int width, height;
+        window.get_size (out width, out height);
+
+        Size size = {
+            width: width,
+            height: height
+        };
+        sizes.insert (window, size);
+
+        return false;
+    }
+
+    private void on_window_removed (Gtk.Window window) {
+        Size? size = sizes.get (window);
+        sizes.remove (window);
+        bool maximized = window.is_maximized;
+
+        if (!maximized && size != null) {
+            settings.set ("window-size", "(ii)", size.width, size.height);
+        }
+        settings.set_boolean ("window-maximized", maximized);
+    }
+
     private void on_quit () {
         base.quit ();
     }
diff --git a/src/app/ui/window.vala b/src/app/ui/window.vala
index 506a354..962805e 100644
--- a/src/app/ui/window.vala
+++ b/src/app/ui/window.vala
@@ -55,8 +55,6 @@ public class WebArchives.Window : Gtk.ApplicationWindow {
 
         this.context = context;
 
-        set_default_size (900, 600);
-
         header_bar = new HeaderBar ();
         header_bar.set_context (context);
         set_titlebar (header_bar);