diff --git a/release-notes/changes/7-fullscreen-maximized b/release-notes/changes/7-fullscreen-maximized
new file mode 100644
index 00000000..d77b9906
--- /dev/null
+++ b/release-notes/changes/7-fullscreen-maximized
@@ -0,0 +1 @@
+mark fullscreen windows as maximized
diff --git a/src/con.c b/src/con.c
index abcc4fba..6daf6ce6 100644
--- a/src/con.c
+++ b/src/con.c
@@ -429,20 +429,20 @@ bool con_is_hidden(Con *con) {
 /*
  * Returns true if the container is maximized in the given orientation.
  *
- * If the container is floating or fullscreen, it is not considered maximized.
- * Otherwise, it is maximized if it doesn't share space with any other
- * container in the given orientation. For example, if a workspace contains
- * a single splitv container with three children, none of them are considered
- * vertically maximized, but they are all considered horizontally maximized.
+ * If the container is floating, it is not considered maximized. Otherwise, it
+ * is maximized if it doesn't share space with any other container in the given
+ * orientation. For example, if a workspace contains a single splitv container
+ * with three children, none of them are considered vertically maximized, but
+ * they are all considered horizontally maximized.
  *
  * Passing "maximized" hints to the application can help it make the right
  * choices about how to draw its borders. See discussion in
  * https://github.com/i3/i3/pull/2380.
  */
 bool con_is_maximized(Con *con, orientation_t orientation) {
-    /* Fullscreen containers are not considered maximized. */
+    /* Fullscreen containers are considered maximized. */
     if (con->fullscreen_mode != CF_NONE) {
-        return false;
+        return true;
     }
 
     /* Look up the container layout which corresponds to the given
diff --git a/testcases/t/551-net-wm-state-maximized.t b/testcases/t/551-net-wm-state-maximized.t
index 81ebcd92..fcd2a067 100644
--- a/testcases/t/551-net-wm-state-maximized.t
+++ b/testcases/t/551-net-wm-state-maximized.t
@@ -57,10 +57,10 @@ subtest 'two windows in default layout', sub {
 };
 
 cmd 'fullscreen enable';
-ok(maximized_neither($winA), 'fullscreen windows are not maximized');
+ok(maximized_both($winA), 'fullscreen windows are maximized');
 
 cmd 'fullscreen disable';
-ok(maximized_both($winA), 'disabling fullscreen sets maximized to true again');
+ok(maximized_both($winA), 'disabling fullscreen retains maximized');
 
 cmd 'floating enable';
 ok(maximized_neither($winA), 'floating windows are not maximized');