Reference: Fataawa al-Lajnah ad-Daa.imah lil-Buhooth al-‘Ilmiyyah wal-Iftaa. – Volume 3, Page 23, Question 1, Fatwa No. 3257
Question: What is the ruling regarding celebrating the birthday of the Prophet ﷺ in the month of Rabee’ al-Awwal in honour of him ﷺ?
Response: Honouring the Prophet and respecting him is by: Believing in all that he came with from Allaah, and following his Sharee’ah and ‘aqeedah verbally, actively and in character, and leaving off innovation in the religion, and from innovation in the religion is celebrating the birthday of the Prophet ﷺ.
And with Allaah lies all success and may Allaah send prayers and salutations upon our Prophet ﷺ and his family and his companions.