Virginia's 31st Senate district is one of 40 districts in the Senate of Virginia. It has been represented by Democrat Barbara Favola since 2012, succeeding retiring fellow Democrat Mary Margaret Whipple. In the 2023 Virginia Senate election, Russet Perry was elected.
District 31 stretches along the Potomac River in parts of Arlington, Fairfax, and Loudoun counties, including some or all of McLean, Langley, Great Falls, and Lowes Island. The sections of Arlington covered include the neighborhoods of Arlington Forest, Arlington View, Ballston, Cherrydale, Clarendon, Courthouse, Glen Carlyn, Lyon Village, Rosslyn, Virginia Square and Westover.
The district overlaps with Virginia's 8th and 10th congressional districts, and with the 34th, 47th, 48th, 49th, and 86th districts of the Virginia House of Delegates. It lies directly across the river from Maryland and the District of Columbia.
All election results below took place prior to 2011 redistricting, and thus were under different district lines.