Assalamu alaikum Sheikh, Is it Sunnah for men to cover their head, such as by wearing a cap, when entering the washroom? Is there any authentic evidence for this practice? JazakAllahu khair.

Ustadh AbdulAziz al-Haqqan

It is not an established Sunnah. The hadith that the Prophet covered his head on entering the toilet is weak (graded so by al-Albani raḥimahullāh).