Zachery (Zach) Ziemek (born February 23, 1993) is an American athlete competing in the decathlon.

Ziemek won the bronze medal at the 2022 World Championships in Eugene with a personal best score of 8676.

[3] He represented his country at the 2015 World Championships in Beijing, where he finished 15th.

[8] Only three other men have ever gone higher in an 8000+pt decathlon: Erki Nool (5.60 m in his 8628, 1998), Aleksandr Averbukh (5.60 m in his 8084, 1997) and Timothy Bright (5.70 m in his 8216, 1988)[9] His main personal bests are 8471 points in the decathlon (Eugene 2021)[10] and 6173 points in the indoor heptathlon (Birmingham 2016).

[4] Ziemek resides in Sun Prairie, WI and trains at his alma mater the University of Wisconsin-Madison.