Is hanging adhkaar on the bathroom door haraam, and what should I do if it is?

There is no harm in writing remembrances (dhikr) and hanging them on walls. As for hanging them on a bathroom door, there is no harm in it if they are not exposed to disrespect, such as if the door opens outwards. Otherwise, hanging remembrances inside the bathroom is disliked (makrooh).

The hadith narrated by Anas ibn Malik, that the Prophet (peace be upon him) used to remove his ring when entering the toilet, is weak. However, it was reported from Ibn Abbas and Ikrimah that the Prophet (peace be upon him) used to remove it because it contained the mention of Allah.

The position of the majority of scholars is that it is disliked to take something containing the remembrance of Allah into the toilet, not forbidden. It is recommended to remove anything that contains the remembrance of Allah. If it is necessary to hang remembrances, it is preferable to move them to a wall adjacent to the door to achieve the benefit and remove the dislike.