The Scotland fly-half will rejoin the Warriors after negotiations about extending his deal with Gloucester stalled, according to RugbyPass.
Hastings has struggled with injury over the past couple of seasons and missed out on the 2023 World Cup squad but was recalled for the Six Nations before being forced out by a knee injury.
Rory Sutherland is another Scotland international expected to be playing his rugby at Scotstoun next season. The British & Irish Lions prop is currently with French Top 14 club Oyannax.