Karen Eileen Spilka is an American politician and attorney serving as a Democratic member of the Massachusetts Senate. She represents the towns of Ashland, Framingham, Holliston, Hopkinton, Medway and Natick in the MetroWest region of Massachusetts. She has served as the 95th President of the Massachusetts Senate since July 2018. Previously she served as a member of the Massachusetts House of Representatives from 2001 to 2005.

The Massachusetts Senate is the upper house of the Massachusetts General Court, the bicameral state legislature of the Commonwealth of Massachusetts. The Senate comprises 40 elected members from 40 single-member senatorial districts in the state. All but one of the districts are named for the counties in which they are located. Senators serve two-year terms, without term limits. The Senate convenes in the Massachusetts State House in Boston, the state capital.