Kelley Square is a square located in Worcester, Massachusetts, at the intersection of Massachusetts Route 122 and 122A, with ramp access to and from Interstate 290.

Cornelius F. Kelley, who died of wounds received in battle in Verdun, France, on October 13, 1918.

[1] With a complex convergence of multiple roads, the square has previously been ranked as the state's most dangerous intersection, and as of 2019[update] was ranked as the eighth-most dangerous intersection in Massachusetts.

‡ Per traffic flow changes implemented in May 2020[3] In October 2019, officials held a groundbreaking for the Kelley Square Improvement Project, a $240 million redevelopment project that includes construction of Polar Park, a new minor league baseball stadium, along with hotels and apartments, as well as reconstructing the square as a modified roundabout.

[4] As part of the project, the Massachusetts Department of Transportation (MassDOT) permanently reversed the direction of traffic flow on Millbury Street, and Harding Street south of the square, effective May 6, 2020.