The 21-year-old, who featured for the Latics against the European champions last week, agreed personal terms to complete his switch to Stamford Bridge. No details were released regarding the fee or the length of Moses' contract.
Wigan chairman Dave Whelan accused Chelsea last week of "messing about" over the fee to be paid for Moses, with the Blues' offers up to that point conditional on add-ons and Wigan thought to be holding out for around £9million.
A bid was finally accepted on Thursday and Moses was given permission to discuss personal terms.
Moses represented England up to under-21 level before switching allegiance to Nigeria for his senior international career.
He emerged from Crystal Palace's academy to make his first-team debut in 2007, before joining the Latics in 2010 and making 74 league appearances with eight goals.
A statement on Chelsea's official website read: "Chelsea Football Club is delighted to announce the signing of Victor Moses from Wigan Athletic.
"The 21-year-old winger's last appearance in Wigan colours came in Chelsea's 2-0 win at the DW Stadium last weekend, when he caught the eye with his strong running out wide."
Moses became Chelsea boss Roberto Di Matteo's second signing of the day, following the earlier capture of Marseille full-back Cesar Azpilicueta.
The 22-year-old, who played for Spain in this summer's Olympics, arrived this morning for a reported £7m.
Source: PA
Source: PA