Joseph Donald Keener (born April 21, 1953) is an American former professional baseball pitcher who appeared in two games for the Montreal Expos of Major League Baseball in . Born in San Pedro, California, Keener graduated from Quartz Hill High School and attended Antelope Valley College. He threw and batted right-handed and was listed as tall and .
Keener signed with Montreal as an undrafted free agent in 1973 and spent his full, seven-year professional career in the Expos' organization. His two MLB games, both starting pitcher assignments, came in the waning days of the Expos' 107-loss 1976 campaign. On September 18, at Jarry Park Stadium against the St. Louis Cardinals, he lasted only one-third of an inning, giving up three hits, four earned runs, three bases on balls, and a balk, and was charged with the Expos' eventual 7–4 loss. Eight days later, against the New York Mets at Shea Stadium, he permitted four hits, five bases on balls, and one earned run in four full innings, and did not earn a decision in Montreal's 5–4 setback.
Over his two major-league appearances, Keener posted a 0–1 record and 10.38 earned run average, allowing five earned runs in 4 innings pitched on seven hits and eight bases on balls; he struck out one. In the minor leagues, Keener posted a stellar 66–37 won–lost mark and .641 winning percentage, with four seasons of double-digit victories over his seven-year career.