The Ruger SP101 is a series of double-action revolvers produced by the American company Sturm, Ruger & Co. The SP101 is a small frame and all-steel-construction carry revolver, with a five-shot (.38 Special, .357 Magnum, and 9×19mm Parabellum), six-shot (.327 Federal Magnum and .32 H&R Magnum), or eight-shot (.22 LR) cylinder.

The Ruger SP101 was introduced in 1989 as the smaller-frame counterpart to the GP100. Both of these revolvers, together, replaced Sturm, Ruger & Co's long-standing staple in the American firearms market, the Ruger Security-Six series revolvers. A 9 mm version was available until its discontinuation around 1998, but was later re-released in early 2018. A basic .22 LR version was also available until 2003 while a redesigned version was introduced in 2011.