The 1991 National League Championship Series was played between the Atlanta Braves (94–68) and the Pittsburgh Pirates (98–64), with the Braves coming out on top in the Series 4–3. It was considered one of the best-pitched seven-game series of the modern era, featuring three 1–0 finishes and four shutouts. The Braves went on to lose in the World Series to the Minnesota Twins in seven games.

The Pirates had the best record in the National League in 1991, and were the first NL East team to win consecutive division championships since the Philadelphia Phillies, their in-state rivals, during their run of three straight NL East championships, from 1976–1978 (The Pirates won the NL East in a game against their rivals), and were expected to win this Series and advance to the World Series. But the Braves, who went from last place in the National League West in 1990 to first place in the division in 1991, were able to pull off the upset in their memorable run to the World Series versus the Minnesota Twins.