Lee has supported a number of efforts to reform cannabis laws in Congress. In 2018 she introduced the Marijuana Justice Act to remove cannabis from the Controlled Substances Act, penalize states that enforce cannabis laws disproportionately (regarding race or income status), and enact other social justice-related reforms. Additional legislation Lee has introduced includes the States' Medical Marijuana Property Rights Protection Act, Veterans Medical Marijuana Safe Harbor Act, Restraining Excessive Federal Enforcement & Regulations of Cannabis (REFER) Act, and the Realizing Equitable & Sustainable Participation in Emerging Cannabis Trades (RESPECT) Resolution. Lee was an original cosponsor of the Ending Federal Marijuana Prohibition Act when it was first introduced in 2011. In January 2019 she was named a co-chair of the Congressional Cannabis Caucus.