Michael Adebolajo (28), of Romford, Essex, was charged with the attempted murder of two police officers and possession of a firearm.
He has been remanded in custody to appear in Westminster Magistrates Court on Monday.
Michael Adebowale, 22, has already been charged with the soldier's murder and appeared in court on Thursday.
Adebowale, of Greenwich, south-east London, was remanded in custody and is due to appear at the Old Bailey, London, on Monday.
He was charged after spending six days in hospital, having been shot by police and arrested following the attack on 22 May.
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Both Adebowale and Adebolajo were filmed and photographed by witnesses following the attack, which took place on a busy street during the afternoon.
On Wednesday, a post-mortem examination found Drummer Rigby, from Middleton, Greater Manchester, died of "multiple incised wounds" after the attack.
The total number of arrests made in connection with the attack stands at 12.
So far, eight of those arrested have been bailed and two released without charge.
On Friday, Drummer Rigby's family appealed for calm after reports of a rise in anti-Muslim incidents following the killing.