The state Assembly will debate the right-to-work bill in an overnight session that is scheduled to end 9 a.m. Friday.
Under right-to-work, workers in unionized workplaces are allowed to opt out of paying union dues. Supporters of the bill say it is about having a choice and workplace freedom, while opponents say the bill dismantles private sector unions.
The Senate passed the legislation on a 17-15 vote on a largely party-line vote, with one Republican senator voting against.
Gov. Scott Walker has said he would sign the bill if it reaches his desk. The bill would make Wisconsin the 25th state in the country with a right-to-work law.
The Assembly debate, which began Thursday morning and Wisconsin Eye is streaming, can be watched below.