Oxford have made Jonathan Meades their first signing of the summer, while Scott Davies and Deane Smalley have signed new deals at the League Two club.
Wales Under-21 international midfielder Meades was released by Bournemouth having spent a successful loan spell at AFC Wimbledon last term.
He has now penned a two-year contract with the U's.
Davies impressed at the Kassam Stadium after joining in March and he has now joined Smalley in signing a new one-year contract.
Davies told the club's official website: "It's a great club, everyone has made me feel very welcome and I am looking forward to a successful season."
Smalley added: "I have enjoyed my time here and feel I have more to give.
"I was pleased with my game last season and contribution to the team, but know I need more goals.
"I am confident I can add that to my game next season and can't wait to report back again."