diff --git a/.changelog/32933.txt b/.changelog/32933.txt
new file mode 100644
index 00000000000..6edd72b9cd9
--- /dev/null
+++ b/.changelog/32933.txt
@@ -0,0 +1,3 @@
+```release-note:bug
+resource/aws_appstream_fleet: Increased upper limit of `max_user_duration_in_seconds` to 432000
+```
diff --git a/internal/service/appstream/fleet.go b/internal/service/appstream/fleet.go
index b54236fd7b4..0f8c6f603ab 100644
--- a/internal/service/appstream/fleet.go
+++ b/internal/service/appstream/fleet.go
@@ -158,7 +158,7 @@ func ResourceFleet() *schema.Resource {
 				Type:         schema.TypeInt,
 				Optional:     true,
 				Computed:     true,
-				ValidateFunc: validation.IntBetween(600, 360000),
+				ValidateFunc: validation.IntBetween(600, 432000),
 			},
 			"name": {
 				Type:     schema.TypeString,