Efforts to increase inclusion in science face multiple barriers, including cultural and social behaviors in settings such as academic conferences. Conferences are beneficial, but the culture can promote inequities and power differentials that harm historically underrepresented groups. Science suffers when conference culture propagates exclusion and discrimination that leads to attrition of scientists. Codes of conduct represent a tool to shift conference culture to better support diverse scientists and clearly detail unacceptable behaviors. We examined the prevalence and content of codes of conduct at biology conferences in the United States and Canada. We highlight how codes of conduct address issues of sexual misconduct and identity-based discrimination. Surprisingly, only 24% of the 195 surveyed conferences had codes. Of the conferences with codes, 43% did not mention sexual misconduct and 17% did not mention identity-based discrimination. Further, 26% of these conferences failed to include a way to report violations of the code and 35% lacked consequences for misconduct. We found that larger and national conferences are more likely to have codes than smaller ( = 0.04) and international or regional ( = 0.03) conferences. Conferences that lack codes risk creating and perpetuating negative environments that make underrepresented groups feel unwelcome, or worse, actively cause harm. We recommend that conferences have codes that are easily accessible, explicitly address identity-based discrimination and sexual misconduct, provide channels for anonymous impartial reporting, and contain clear consequences. These efforts will improve inclusivity and reduce the loss of scientists who have been historically marginalized.