Question: Is there a problem in birthday celebration in terms of Islam?
We need to evaluate birthday celebrations in regards to its purpose and consequences. If the purpose is to share the happiness of being at a certain age with friends and relatives, and to have a good time together, it could be considered as “reasonable and permissible” on condition that it is within the legitimate limits. However, if these celebrations are made an instrument to imitate and envy foreign cultures like the new year celebrations, or the legitimate limits are transgressed, it would certainly be wrong.
 APAYDIN, Yunus; Catechism of the Presidency of Religious Affairs, vol.2, Islam and Society, p.483