Governor Jay Nixon signed a bill banning the substance Tuesday afternoon in West Plains, Missouri.
The ban doesn’t go into effect until August 28.
After then, anyone caught with K2 will be punished with a fine or jail time.
K2 is a synthetic marijuana usually made when synthetic compounds are sprayed on dried herbs or flowers.
Missouri is the 5th state to ban K2.
Arkansas is one of those five states, however the ban is not permanent at this time.
Last Friday, Governor Mike Beebe signed an emergency ban on the controversial drug.
The ban lasts 120 days.
Arkansas lawmakers say the legislature may look into a permanent ban next session.