Wikipedia
Mehmed (modern Turkish: Mehmet) is the most common Turkish form of the Arabic name Muhammad (Muhammed and Muhammet are also used, though considerably less) and gains its significance from being the name of Muhammad, the prophet of Islam. Originally the intermediary vowels in the Arabic Muhammed were completed with an e, which spelled Mehemed, and the name lost a vowel over time. Final devoicing of d to t is a regular process in Turkish. The prophet himself is referred to in Turkish using the full version, Muhammed.
The name Mehmet also often appears in derived compound names. The name is also prevalent in Turkish influenced cultures, particularly Balkan Muslims (Albania, Bosnia and Kosovo). The name is also commonly used in Turkish culture in the form of Mehmetçik, meaning little Mehmet, for unranked soldiers.