The Smith & Wesson Sigma, was Smith & Wesson's first venture into using synthetic materials in pistol construction, using high-strength polymer material for the frame.

The Sigma series pistols were so similar to the competing Glock pistols that Glock sued Smith & Wesson for patent infringement. The case was settled out of court in 1997, with S&W agreeing to make alterations to the Sigma design and pay an undisclosed amount to Glock.