Donald Albert Hoak (February 5, 1928 – October 9, 1969), nicknamed "Tiger", was an American professional baseball third baseman and coach. He played eleven seasons in Major League Baseball (MLB) (1954–1964) for the Brooklyn Dodgers, Chicago Cubs, Cincinnati Redlegs, Pittsburgh Pirates, and Philadelphia Phillies.

Hoak broke into the professional baseball in 1947 after a stint in the United States Navy towards the end of World War II. He signed with the Brooklyn Dodgers organization and worked his way up the organization based almost solely on his glove, speed on the bases and tenacity. In 1954, Hoak's patience was rewarded by a spot on the Dodgers' roster.

During his two seasons with the Dodgers, Hoak shared third base duties with Jackie Robinson and Billy Cox. In 1955, the Dodgers defeated the New York Yankees in the World Series to win their only championship in Brooklyn. Hoak played third base in place of Robinson in the seventh and deciding game of that Series—the only World Series game Robinson did not play in during his career when his team was in the World Series.

After the season, Hoak was traded to the Chicago Cubs. In 1956, Hoak batted .215 with 5 home runs and 37 runs batted in, and also set a National League record by striking out six times in one game, against six different pitchers, in which 48 players were used in a 17-inning marathon on May 2, won by the visiting New York Giants 6-5.

After the 1956 season, the Cubs traded Hoak to the Cincinnati Redlegs in a five-player deal. In 1957 Hoak improved his batting average to .293, after leading the league well into May at over .400, and set career highs in home runs (19) and runs batted in (89), as well as leading the National League in doubles with 39. In a game against the Milwaukee Braves on April 21, Hoak was involved in a controversial play that would lead to a change in the rules. He was on second base and teammate Gus Bell was on first, when Wally Post hit a ground ball to short. Hoak broke up a potential double play by fielding the ball himself and flipping it to Milwaukee shortstop Johnny Logan. Hoak was called out for interference, but Post was given a single on the play. The day before, Johnny Temple let Bell's ground ball hit him with the same result, Temple being called out for interference and Bell being awarded a single. The two incidents prompted league presidents Warren Giles and Will Harridge to jointly announce a rule change that declared both the runner and batter out if the runner intentionally interferes with a batted ball, with no runners allowed to advance. (Without the new rule, it was sometimes advantageous for a runner to touch a batted ball, because doing so avoided a double play. In the plays already mentioned, Temple and Hoak were out according to a still-existing rule: a runner is out if a batted ball touches him in fair territory before it touches a fielder, with the batter getting a single and no runner advancing unless forced.)

In 1957 Hoak made his only All-Star appearance, but it also would be mired in controversy—though not of Hoak's doing. At the time, as they do currently, fans had the right to vote for the starters (minus the starting pitchers). As a result, a ballot stuffing campaign by Reds fans resulted in Hoak, Post, Temple, Bell, Ed Bailey, Roy McMillan, and Frank Robinson being voted into the starting lineup. First baseman George Crowe, the eventual team home run leader with 31, was the only Red not selected; the fans instead voted for Stan Musial. (Crowe would be selected to the All-Star team in 1958—the only Red so honored.) Commissioner Ford Frick removed Bell and Post from the starting lineup and replaced them with Willie Mays and Hank Aaron; Bell remained on the team as a reserve, but Post was taken off altogether. Frick also stripped the fans of the right to vote for the starters, which they had held since 1947 and would not hold again until 1970 (ironically, the Reds’ newly opened Riverfront Stadium would host the All-Star Game that year). In the third inning of the 1957 game, Hoak grounded out to shortstop Harvey Kuenn in his only plate appearance. He was replaced by Eddie Mathews.

Hoak batted .261 for the Reds during the 1958 season before being traded, along with Harvey Haddix and Smoky Burgess, to the Pittsburgh Pirates for four players (one of whom was Frank Thomas) in January 1959. It was Hoak's throwing error that cost Haddix his perfect game against the Braves after the pitcher had retired 36 batters in a row on May 26, 1959. The Braves went on to win that game, 1-0. In 1960, Hoak batted .282 on a Pirates team that won the World Series; like the 1955 Brooklyn Dodgers, Pittsburgh defeated the Yankees in seven games. The Pirates won the 1960 Series on Bill Mazeroski's ninth-inning home run in Game Seven. During the Pirates’ championship season, Hoak finished second in National League Most Valuable Player Award vote to teammate Dick Groat.

Hoak batted a career-high .298 during the 1961 season, but slumped to .241 in 1962. After the 1962 season, the Pirates traded him to the Philadelphia Phillies for Pancho Herrera and Ted Savage. He batted .231 during the 1963 season, then was released in May 1964 after making only six plate appearances—all in pinch-hitting roles. Hoak retired forthwith, but returned to the Phillies as a scout for the final month of the season—during which the Phillies lost the pennant to the St. Louis Cardinals by one game after leading the National League by 6 1/2 games with two weeks remaining.