Common material in Matthew and Mark indicate that Matthew was written after Mark. Since Mark dates from AD 45-60 Matthew most likely was written after that. Internal evidence in Matthew indicates it was written prior to the destruction of Jerusalem in AD 70.

Sources:
Encountering the New Testament, Walter A. Elwell / Robert W. Yarbrough, 1998, Baker Books, page 79

A Survey of the New Testament, Third Edition, Robert H. Gundry, 1994, A Survey of the New Testament, Third Edition, Robert H. Gundry, 1994, Zondervan, page 161