Huffman had a good voting record on marijuana while in the state assembly. In 2012, he cast the deciding vote in committee in favor of California's landmark  bill to legalize, tax and regulate cannabis. In Congress, Huffman has co-sponsored reform bills, and introduced bills to deal with illegal marijuana grows on public lands, such as 2013's PLANT Act to direct the US Sentencing Commission to enhance penalties for drug offenses involving use of poisonous chemicals, water diversion, or vegetation removal.