diff --git a/src/ui/command-ui-handler.ts b/src/ui/command-ui-handler.ts
index f23cc78c9f7..5eb5588a9bf 100644
--- a/src/ui/command-ui-handler.ts
+++ b/src/ui/command-ui-handler.ts
@@ -180,9 +180,10 @@ export default class CommandUiHandler extends UiHandler {
 
   canTera(): boolean {
     const hasTeraMod = !!globalScene.getModifiers(TerastallizeAccessModifier).length;
+    const isBlockedForm = globalScene.getField()[this.fieldIndex].isMega() || globalScene.getField()[this.fieldIndex].isMax();
     const currentTeras = globalScene.arena.playerTerasUsed;
     const plannedTera = globalScene.currentBattle.preTurnCommands[0]?.command === Command.TERA && this.fieldIndex > 0 ? 1 : 0;
-    return hasTeraMod && (currentTeras + plannedTera) < 1;
+    return hasTeraMod && !isBlockedForm && (currentTeras + plannedTera) < 1;
   }
 
   toggleTeraButton() {