diff --git a/packages/@adobe/spectrum-css-temp/components/dropdown/index.css b/packages/@adobe/spectrum-css-temp/components/dropdown/index.css
index 9244276783b..4b206cac272 100644
--- a/packages/@adobe/spectrum-css-temp/components/dropdown/index.css
+++ b/packages/@adobe/spectrum-css-temp/components/dropdown/index.css
@@ -27,6 +27,9 @@ governing permissions and limitations under the License.
   inline-size: var(--spectrum-dropdown-width);
   min-inline-size: var(--spectrum-dropdown-min-width);
 
+  /* Ensure that changing the selected item doesn't affect the size of the dropdown and its parents */
+  contain: size;
+
   /* Hack to enable select-powered Dropdowns */
   select {
     appearance: none;