Gov. Scott Walker signed the bill into law Friday, the Milwaukee Journal Sentinel reported. That leaves Illinois as the only holdout.
The law, which also allows the carrying of concealed stun guns, takes effect Nov. 1. It passed the state Legislature last month on a bipartisan vote.
Applicants for permits must go through training and pass background checks. An amendment pushed by some Republicans would have eliminated the permit requirement but was rejected.
"By signing concealed carry into law today we are making Wisconsin safer for all responsible, law abiding citizens," Walker said in a statement.
Concealed weapons will not be allowed in law enforcement agencies, prisons and jails, secure mental-health facilities, courthouses and the secure areas of airports. Government buildings can ban them, but they must be allowed in public parks and other public open areas, including the Statehouse grounds.