diff --git a/addons/web/static/src/core/dialog/dialog.js b/addons/web/static/src/core/dialog/dialog.js
index 23c256e7401..bde2a18f1c2 100644
--- a/addons/web/static/src/core/dialog/dialog.js
+++ b/addons/web/static/src/core/dialog/dialog.js
@@ -82,7 +82,7 @@ Dialog.props = {
     fullscreen: { type: Boolean, optional: true },
     footer: { type: Boolean, optional: true },
     header: { type: Boolean, optional: true },
-    size: { type: String, optional: true, validate: (s) => ["sm", "md", "lg", "xl"].includes(s) },
+    size: { type: String, optional: true, validate: (s) => ["sm", "md", "lg", "xl", "fs"].includes(s) },
     technical: { type: Boolean, optional: true },
     title: { type: String, optional: true },
     modalRef: { type: Function, optional: true },
diff --git a/addons/web/static/src/core/dialog/dialog.scss b/addons/web/static/src/core/dialog/dialog.scss
index 24b593d98cf..e07faedf5bb 100644
--- a/addons/web/static/src/core/dialog/dialog.scss
+++ b/addons/web/static/src/core/dialog/dialog.scss
@@ -17,3 +17,10 @@
         margin: 0; // Reset boostrap.
     }
 }
+
+@include media-breakpoint-up(sm) {
+    .modal-fs {
+        width: calc(100% - #{2 * $modal-dialog-margin-y-sm-up});
+        max-width: none;
+    }
+}