Pruitt's office responded to a request for a stay by lawyers for Charles Warner. In court papers, officials said the execution is now set for Nov. 13.
Warner was scheduled to be put to death at 8 p.m. April 29, two hours after Clayton Lockett. Lockett died of a heart attack 10 minutes after the execution was officially halted, and Warner's execution was rescheduled to May 13.
In its filing with the Court of Criminal Appeals, Pruitt's office said that the six-month stay will allow time for an investigation into how Lockett's execution went wrong.
Warner was sentenced to death for raping and killing his girlfriend's 11-month-old daughter in 1997.
Both Warner and Lockett challenged Oklahoma's secrecy policy on execution drugs. They won a stay from the state Supreme Court, which reversed itself under pressure from Gov. Mary Fallin and the state legislature.
Oklahoma has put 111 people to death since it resumed executions in 1990. The state is second only to Texas and Virginia in the number of executions in the modern era.