The winners -- nine from the American League and nine from the National League -- were announced Tuesday on ESPN.
National League winners also included Chicago Cubs first baseman Anthony Rizzo and shortstop Javier Baez; St. Louis Cardinals second baseman Kolten Wong and left fielder Tyler O'Neill; San Diego Padres center fielder Trent Grisham; Cincinnati Reds catcher Tucker Barnhart; and Atlanta Braves pitcher Max Fried.
American League winners included Cleveland Indians catcher Roberto Perez and second baseman Cesar Hernandez; Texas Rangers right fielder Joey Gallo and third baseman Isiah Kiner-Falefa; Seattle Mariners first baseman Evan White and shortstop J.P. Crawford; Kansas City Royals left fielder Alex Gordon; Chicago White Sox center fielder Luis Robert; and Los Angeles Angels pitcher Griffin Canning.
Betts -- who also is a finalist for the National League MVP award -- earned the honor for the fifth time of his career. He had 113 putouts, four errors and an assist in 52 outfielder appearances in 2020.
Arenado was named the best-fielding third baseman in the National League the eighth time in his eighth season. He had 43 putouts and made just three errors in 48 games at the position.
Rizzo and Gordon each earned the honor for the fourth time. Wong and Perez each won Gold Glove Awards for a second time.
Robert and White won as rookies. Canning, Gallo, Hernandez, Crawford, Kiner-Falefa, Barnhart, O'Neill, Grisham, Fried and Baez are also first-time Gold Glove Award winners.
Silver Slugger award winners will be announced on Thursday on MLB Network.
The winners of the other American League and National League awards will be announced from Nov. 9 to Nov. 12 on MLB Network. Each segment of those broadcasts will start at 6 p.m. EST.