Gündüz Tekin Onay (31 May 1942 in Çankırı – 4 January 2008 in İstanbul, Turkey) was a Turkish footballer and coach who also trained Istanbul club Beşiktaş between 1976 and 1977. He is known for his success in discovering starlets and for his modesty. Additionally, he was the author of a system to explore and breed young talents for Turkish football.