Pērkonkrusts (Thunder Cross in Latvian), was a Latvian political party founded in the 1930s. This group adapted fascist ideology to the situation in independent Latvia after 1918. It was the largest and longest-lived organisation of its kind in Latvia. The movement's leader was Gustavs Celmiņš.

Pērkonkrusts has been variously categorised by scholars as representing the radical right, "activist nationalism" (Latvian: aktīvais nacionālisms), or fascism, with the latter term being the most commonly encountered in the scholarly literature.Roger Griffin, a prominent fascist studies scholar, describes Pērkonkrusts in the 1930s as having been a "small but genuine fascist opposition" which "pursued a revolutionary solution to the [economic] crisis and which would turn Latvia into an authoritarian state based on a new élite with a new corporatist economy", with its politics defined by "integralist nationalism".

Aside from the party's newspaper, Pērkonkrusts (1933–34), the main source of information on the political platform of Pērkonkrusts can be found in the 1933 brochure, Pērkonkrusts: What Is It? What Does It Want? How Does It Work? (Latvian: Kas ir? Ko grib? Kā darbojas? Pērkonkrusts). This publication not only outlined the movement's political programme, but also included the complete party statutes.