This journal examines the prohibition on transgender marriage according to Buya Hamka in the Al-Azhar commentary book. Transgender is a symptom of a person's dissatisfaction because they feel there is no match between their physical form and genitals and their mental state or because they are dissatisfied with their genitals. The final results of this research can be concluded, namely: The prohibition of transgender according to Hamka is based on an-Nisa' verse 119, ar-Rum verse 30 and al-Baqarah: 216, hadith, ijma' and fatwa, that transgender behavior is actions and behavior that being deceived by Satan and following one's desires, including the act of changing Allah SWT's creation, transgender is an act that does not function Allah's creation according to its function, according to nature. Transgender is the act of resembling the opposite sex, the perpetrator received a curse from Rasulullah S.A.W and is classified as a Haram act. According to Buya Hamka, the prohibition on transgender marriages means same-sex marriages occur, sexual intercourse is not in accordance with nature, there is no fertility (procreation), the goal of marriage cannot be achieved, and the five basic principles of religion are threatened, namely religion, reason, the right to life, property and offspring. Genital surgery carried out by transgender people causes greater harm. Islam is determined by external aspects or physical indications, not psychologically.