Alejandro Peña Vásquez [ah-leh-hahn'-dro / pen'-nya / vahs'-kes] (born June 25, 1959) is a Dominican former relief pitcher in Major League Baseball.

Peña made his Major League debut on August 13, 1981 (in time to be included on the roster for the 1981 National League Championship Series, although he did not appear in the 1981 World Series), and made his last appearance on April 13, 1996, while pitching for the Los Angeles Dodgers (1981–1989), New York Mets (1990–1991), Atlanta Braves (1991–1992; 1995), Pittsburgh Pirates (1994), Boston Red Sox (1995) and Florida Marlins (1995; 1996).

Pena became a full-time starting pitcher in 1983 and 1984, winning the ERA title in 1984 with 2.48 earned run average and leading the league with four shutouts.

In the 1988 World Series, Pena pitched the 8th and 9th innings of Game 1, allowing one hit, striking out three, and picking up the win after Kirk Gibson's famous home run.

He was on the mound for the final pitch of that classic series, giving up the base hit to Gene Larkin that won the title for the Minnesota Twins.