Wisconsin is an open carry state. They have complete state preemption for firearms laws. However, you may not openly carry a firearm in a vehicle.
Legal Disclaimer We make every effort to provide correct information on this site. However, the legal landscape surrounding open carry is fluid and subject to a myriad of political influences in the various states. Therefore, any and all information you glean from this site should be independently verified!
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State Constitution Article I, Section 25

The people have the right to keep and bear arms for security, defense, hunting, recreation or any other lawful purpose.

Minimum Age to OC 18
Preemption Complete State Preemption of All Firearm Laws

NOTE: Almost all states allow local regulation of the discharge of firearms

Open Car Carry You may NOT open carry in a car.
Private Sales Not Yet Determined
Permit Issued Not Yet Determined
K-12 Carry Not Yet Determined

NOTE: The Federal Gun-Free School Zones Act Restricts Carry to Permit Holders

College Carry Carry Prohibited by Statute

NOTE: Even if Legal, Students May be Subject to Academic Sanctions

Places Off Limits
    Currently Being Researched
State Law
Case Law In Wisconsin, a gun in plan sight inside a vehicle is both in violation of the encased requirement, Section 167.31, and considered unlawfully concealed. 
State v. Walls, 526 N.W.2d 765 (Wis. App. 1994) (A handgun on the seat of a car that was indiscernible from ordinary observation by a person outside, and within the immediate vicinity, of the vehicle was hidden from view for purposes of determining whether the gun was a concealed weapon under this section). See also State v. Keith, 498 N.W.2d 865 (Ct. App. 1993) (To .go armed. does not require going anywhere. The elements for a violation of s. 941.23 are: 1) a dangerous weapon is on the defendant.s person or within reach; 2) the defendant is aware of the weapon.s presence; and 3) the weapon is hidden).
An encased gun is unlawfully concealed in a vehicle if the case is not “out of reach,” arguably wingspan plus lunge distance.
State v. Alloy, 616 N.W.2d 525 (Wis. App. 2000) (affirming concealed carry conviction of man possessing handgun in a vehicle in conformity with Wisconsin Stat. § 167.31 because Alloy’s argument is based on the false assertion that he was trapped by a conflict between Wis. Stat. § 167.31 and Wis. Stat. § 941.23. A person transporting a firearm is governed by both statutes. To comply with § 167.31, the person must encase the weapon. To comply with § 941.23, he or she must place the enclosed weapon out of reach. See State v. Asfoor, 75 Wis.2d 411, 433-34, 249 N.W.2d 529 (1977). A person complying with § 167.31 is not required to violate § 941.23. The encased weapon can be lawfully transported out of reach..)

Locking the gun in the glove box is also still unlawful concealment.
State v. Fry, 388 N.W.2d 565 (Wis. App. 1986) (defendant was properly convicted under this section for driving a vehicle with a gun locked in a glove compartment).

Official Documents
State Organizations
Local Ordinances
Concealed Carry Available at Handgunlaw.us