The third season of "The Summer I Turned Pretty" (TSITP), which concluded on September 17, 2025, is indeed the final season of the series. It is based on the third and last book in Jenny Han's trilogy, "We'll Always Have Summer." There are no plans for a fourth season as this season wrapped up the story of Belly and her romantic journey. While the season ended with its eleventh episode, there was some speculation about a possible bonus episode, but this did not materialize as part of the series. However, the story is not entirely over: Amazon Prime Video has officially greenlit a feature film that will conclude the story of TSITP, providing fans with a continuation and conclusion beyond the series finale. So while Season 3 is the last TV season, the narrative will continue in film form.

In summary, Season 3 is the last season of the TV show TSITP, but the franchise is continuing with a concluding movie.