Robert George Kline [Junior] (December 9, 1909 – March 16, 1987) was a pitcher in Major League Baseball who played for three teams between the 1930 and 1934 seasons.

A fastball thrower, Kline started and filled various relief roles coming out of the bullpen as a closer, middle reliever, and set-up man.

At the end of the season, Kline was sent by Boston, along with Rabbit Warstler and cash, to the Athletics in a transaction that brought Lefty Grove, Rube Walberg and Max Bishop to the Red Sox.

He split the season with Philadelphia and Washington, collecting seven relief wins to lead the American League pitchers after his contract was sold to the Senators on June 23, 1934.

In a five-season career, Kline posted a 30–28 record with 87 strikeouts and a 5.05 earned run average in 148 appearances, including 37 starts, eight complete games, one shutout, seven saves, and 441⅔ innings of work.