Background: Cannabis criminalization disproportionately harms communities of color in the United States. In Massachusetts’ legal recreational (“adult-use”) cannabis industry, state regulations intend to promote diverse participation. We assessed short-term racial/ethnic and gender diversity across the industry and in senior-level positions with greater opportunities to build wealth (i.e., board members, executives, directors). Methods: We extracted race/ethnicity and gender from required registration forms submitted to state regulators for each person working in a licensed adult-use cannabis business from October 2018 to April 2020 (n=4,883). We conducted descriptive analysis and negative binomial regression to assess characteristics associated with senior positions. Results: As of April 2020, racial/ethnic and gender diversity in the Massachusetts adult-use cannabis market (n=4,883) was 75% white, 7% Latino, 6% Black/African American, similar to the state labor market, and 65% male. Diversity was more limited in senior positions. Agents in senior positions (n=403) were 84% white, 2% Latino, 5% Black/African American, and 82% male. Senior-level participation was markedly low for women of color. Conclusion: Despite legislative and regulatory commitment, diversity lacks in senior positions in this emerging cannabis market. States considering adult-use cannabis markets, and those that have already done so, should monitor participation to identify inequities and adapt initiatives to ensure Black/African American and Latino communities socially and economically benefit from state legalization.