The 29-year-old, whose new deal includes an option to extend by a further 12 months, has become a crucial player for Sebastian Hoeneß's side since signing for Stuttgart from Brighton and Hove Albion in an initial loan deal in summer 2023.
In 86 Bundesliga appearances for the club so far, Undav has scored 46 goals and assisted 18 times, firmly establishing himself as one of the division's top forwards.
Watch: Deniz Undav's brace against Augsburg on Matchday 27
