The Smith & Wesson Model 686 is a double action revolver of US origin that was introduced in the early 1980's. It was developed to produce a stronger framed revolver than the variants of the ubiquitous Model 10, but retaining the smaller grip and size.

The Model 686 is a double action revolver that uses what Smith & Wesson calls an L-frame. The L-frame combines the heavy frame of the earlier N-frame revolvers with the smaller grip of the K-frame revolvers. Different model numbers indicate the use of a blue steel or stainless steel frame and the use of fixed or adjustable sights. It is available with a variety of barrel lengths ranging from 2.5 to 8.75 inches.

The Model 686 fires the .357 Magnum round from a 6 shot cylinder. As with most .357 Magnum revolvers it is also able to fire the smaller and less powerful .38 Special round. Some variants feature a 7 shot cylinder. Effective range is a few dozen meters.

The Model 686 and its variants were mainly aimed at the US civilian and law enforcement market. In the 1980's revolvers already received much competition from pistols and adoption of new service revolvers was lower than the decades before. The M686 was acquired for law enforcement and special forces uses by several others nations.