Ypäjä is a municipality located in the countryside of South-Western Finland. It belongs to the province of Southern Finland and the region of Tavastia Proper. The municipality has a population of 2,189 (31 October 2024) and covers an area of 183.25 square kilometres (70.75 sq mi) of which 0.5 km (0.19 sq mi) is water. The population density is 11.98 inhabitants per square kilometre (31.0/sq mi). The municipality is unilingually Finnish.

The main population centre of Ypäjä is a small village situated on the river Loimijoki, between the towns of Forssa (23 km to the east from Ypäjä) and Loimaa (15 km to the west). Although officially part of the Forssa region, Ypäjä is often also considered to belong to the Loimaa region as it has traditionally been influenced by both towns. Besides Loimaa, its direct neighbours are Jokioinen, Humppila, Somero and Koski Tl.

The distances from Ypäjä to the three major cities in southern Finland are relatively short: 74 kilometres (46 mi) to Turku, 96 km (60 mi) to Tampere, and 132 km (82 mi) to the capital Helsinki.

Ypäjä is probably best known for horses; the municipality e.g. has an Equine College and hosts an annual international riding competition called Finnderby.

Ypäjä's coat of arms is designed by Aukusti Tuhka.

Media related to Ypäjä at Wikimedia Commons

• Municipality of Ypäjä – Official website (in Finnish)
• Ypäjä Equine College