Ronald Matthew Mahay (pronounced /məˈheɪ/) (born June 28, 1971 in Crestwood, Illinois) is a relief pitcher for the Minnesota Twins. He is married and has three children; daughters Mackenzie and Madison and son, Mason.

Mahay was drafted as an outfielder in the 18th round of the Major League Baseball Draft in 1991 by the Boston Red Sox out of South Suburban College, a junior college in South Holland, Illinois, where he both pitched and played center field. When the 1994 Major League Baseball strike lasted into spring training the following year, Mahay was one of the replacement players called up by the Red Sox. As a consequence, Mahay (and all other 1995 replacement players who later made the big leagues) is not eligible for membership in the Major League Baseball Players Association.

Mahay made his Major League debut with the Red Sox on May 21, 1995, as an outfielder, and appeared in five games, batting .200 with four hits in 20 at-bats, including two doubles and a home run. However, he was returned to the minors after a month. In 1996, Mahay moved from the outfield to the pitching mound. He returned to Boston for the latter half of 1997, but was waived after the 1998 campaign. The Oakland Athletics claimed him off the waiver wire, but he saw limited action with the team before being traded to the Florida Marlins in May 2000. While pitching for the Marlins, Mahay recorded his last two Major League hits, a single and a double, in four at-bats. After a "cup of coffee" in the San Diego Padres organization, Mahay signed with the Chicago Cubs, remaining with the team until the end of 2002.