Forbes, 27, will join the Bucks after four seasons with the San Antonio Spurs. He started in all but one of his 63 appearances last season, scoring 11.2 points per game on 38.8% shooting from three.
The combo guard went undrafted in 2016 but latched on in San Antonio after an impressive showing in Summer League that year. He joins D.J. Augustin and Bobby Portis as Milwaukee's reported major free-agent signings for the 2020-21 campaign.