Adams has signed a five-year contract at the Vitality Stadium to make a swift return to the top flight following Leeds' relegation from the Premier League last season.
The 24-year-old only joined Leeds from RB Leipzig last summer and made 24 appearances in the Premier League but his season ended early in March due to a hamstring injury.
Adams has posted on social media after severing ties with Leeds: “Not an easy goodbye. The club, my teammates and the fans have supported me since day 1, and I wish I could’ve given more in the home stretch. Forever grateful for this past year.”
"We're thrilled to have brought Tyler to the club and he is a player we've admired for a long time," Bournemouth chief executive Neill Blake said in a statement.
"It's been widely documented how much his talents have been recognised in this transfer window by other clubs, so to have him sign for AFC Bournemouth shows the ambition we have as a club.
"Tyler is an exciting player who possesses plenty of experience for someone that is just 24 years of age and we're looking forward to working with him as he's a player we know will be a great addition to our squad."
Adams has been given the number 18 jersey at his new club.
He was captain of the US at the 2022 FIFA World Cup in Qatar.
