The role of cognitive schemas on sexual functioning has been studied in samples of heterosexual men and women. However, there are no published studies on the impact of cognitive schemas on sexual functioning in gay men or lesbian women. The current study analyzed the differences in cognitive schemas associated with negative sexual events in a sample of heterosexual and homosexual men and women, with and without sexual problems. A total of 168 women and 148 men completed a web-survey. Participants answered questions about self-perceived sexual problems, and completed the Questionnaire of Cognitive Schemas Activated in Sexual Context. Results for men and women were analyzed in separate MANOVAs (sexual problems 9 sexual orientation). Men with sexual problems scored significantly higher in negative cognitive schemas when facing an adverse sexual episode compared with sexually healthy men, regardless of sexual orientation. Women with sexual problems also scored significantly higher in Undesirability/rejection, Incompetence, and Difference/loneliness schemas when compared women without sexual problems, regardless of sexual orientation. Also, sexual orientation was also found to have a significant effect among women, with lesbian women activating significantly more Undesirability/rejection, Difference/loneliness, and Helpless schemas, than heterosexual women. Overall, findings suggest that, despite some specific patterns particularly in lesbian women, the role of cognitive schemas on sexual functioning is very similar in heterosexual and homosexual men and women. These results highlight the core role of cognitive factors on sexual problems in gay men and lesbian women.