Objectives To understand the ethical principles guiding college students’ abstention from pharmacological cognitive enhancement, and to determine the correlates associated with endorsing different principles. Design One-stage cluster sampling was used to implement a paper-based survey among undergraduate students attending one university in the U.S. Thematic analysis was used to explore the ethical principles guiding PCE abstention. Multivariate logistic regression analyses were used to examine sociodemographic correlates associated with endorsed ethical principles. Participants Of the 499 eligible students who completed the survey, (...) 259 students had a negative attitude towards PCE, did not engage in PCE, and provided reasons for abstention. Results The thematic analysis resulted in the identification of eight themes, with respondents often endorsing more than one theme per response. The three themes most endorsed were non-malfeasance, disapproval of drugs and dosage beneficence. The sociodemographic correlates associated with endorsing each theme varied across themes. Conclusions Students abstain from PCE for a multitude of reasons, many of which are guided by ethical principles. These findings may be incorporated into future prevention programming messages. (shrink)