The 23-year-old midfielder initially moved to Molineux on loan during the summer and has now agreed a deal that runs until 2016 having impressed during 18 appearances to date.
Doumbia fired his second goal for the club during Saturday's dramatic 3-3 draw with Brighton on Saturday.
"In the short time Tongo has been here we have already seen how quickly he has settled and what he can offer us," boss Stale Solbakken told Wolves' official website.
"I am also confident that when he gets even more used to the country and to his team-mates then his game will grow even more and he will get better and better.
"I am delighted we have signed him permanently and I think he can be an important player for Wolves for the next few years."