Joensuu is a Finnish surname. Notable people with the surname include:
Jasmi Joensuu (born 1996), Finnish cross-country skier Jesse Joensuu (born 1987), Finnish ice hockey player Jouni Joensuu (born 1962), Finnish association football manager Matti Yrjänä Joensuu (1948–2011), Finnish writer Timo Joensuu (born 1959), Finnish oncologist