Walter E. Lonergan (September 22, 1885 – January 23, 1958) was a second baseman in Major League Baseball who played briefly for the Boston Red Sox during the 1911 season.

Listed at 5 ft 7 in (1.70 m), 156 lb., Lonergan batted and threw left-handed.

In a 10-game career, Lonergan was a .269 hitter (7-for-26) with two runs, one RBI, and one stolen base.

[citation needed] Lonergan died in Lexington, Massachusetts, on September 6, 2005 at age 72.

This biographical article relating to an American baseball second baseman is a stub.