That includes Amazon.com, which means shoppers who live in Illinois need to pay the tax.
The legislation was passed to allow brick-and-mortar stores to compete with online shopping, ensuring the state's long-term economic stability via "main street businesses," Quinn said.
The Illinois Department of Revenue estimates it misses out on $153 to $170 million in uncollected sales taxes each year from online purchases.
"I believe this law is an important step in leveling the playing field for Illinois businesses," said Senate Pres. John Cullerton, a sponsor of the bill, in a statement.
A press release issued by jcpenney applauded the measure.
"This new law will close the loophole that out-of-state, online-only retailers have used to avoid collecting sales taxes that local Illinois businesses must collect. A sale is a sale."