Ms Rudd quit as Home Secretary in April over her handling of the Windrush scandal which saw some West Indian people hit by uncertain immigration status.
The 55-year-old MP for Hastings and Rye admitted having “inadvertently misled” MPs over targets for removing illegal immigrants but a subsequent inquiry found she was let down by officials.
Her return to the frontbench was backed by fellow Cabinet members Sajid Javid and Liz Truss.
Mr Javid tweeted: “Thrilled to see @AmberRuddHR back in the Cabinet!”
Ms Truss also took to Twitter, writing: “Great to have @AmberRuddHR back at the Cabinet table. #ruddygood.”
North East Cambridgeshire MP Steve Barclay has replaced Dominic Raab as Brexit Secretary, it was announced this afternoon, after Mr Raab resigned yesterday following Mrs May’s draft deal with the EU.