Holy Trinity Greek Orthodox Church is located in Sioux City, Iowa, United States.

Designed by architect William L. Steele, the church building has been listed on the National Register of Historic Places since 1998.

Before the founding of Holy Trinity Church in 1918 (1918), Greek Orthodox Christians had to travel to Omaha, Nebraska to attend services.

Paikos K. Pappaphilipopoulos, who would Americanize his name to "Peter Nelson", led the organization of a church.

Christ Kamages of San Francisco served as architect for the renovation while iconographer Elias Damianakis of Florida and woodcarver Steve Kavroulakis of Crete designed and built a new altar, sanctuary, narthex, iconostasion, and iconography.