The 25-year-old joins from Bristol Rovers on loan for the rest of the season.
Gibbons came through the Port Vale Academy from the age of 11, to establish himself as a first team regular in 2016.
He spent six seasons with the club, earning a promotion to League One along the way, before making the switch to Bristol Rovers in 2022.
He now joins the U’s to help add to Neil Harris’ defensive options, becoming Cambridge’s second January signing after attacker Lyle Taylor.
He will wear the number 26 shirt subject to EFL approval.
Record knife amnesty results for Cambridgeshire
Cambridge crowned busiest station in the East
20mph speed limit approved for Wicken
Regulators raise "serious" Cambridge Water concerns
