The Torah says that a person is not permitted to dress in the clothing of the opposite gender, but I’ve seen people do this when they dress up in Purim costumes. Is this permitted?
This practice is not accepted by all authorities. Some permit wearing one item of the opposite gender.
The reason for this is because the Torah’s prohibition against dressing in the opposite gender’s clothing is to prevent immoral behavior. On Purim, people are not dressing up for immoral purposes, but rather to increase the merriment of this joyous day, and bring smiles and laughter to others.
Therefore, these authorities rule that such costumes are permitted. However, Mishnah Berurah states that many authorities do not allow this practice even on Purim.