Minority stress is often cited as an explanation for greater mental health problems among lesbian, gay, and bisexual (LGB) individuals than heterosexual individuals. However, studies focusing on sex or sexual orientation differences in level of minority stress and its impact on mental health are scarce, even more so outside the United States. Performing secondary analyses on the data of a Dutch population study on sexual health, the present study examines the robustness of the minority stress model by explaining mental health problems among men and women with mostly or only same-sex sexual attraction, and men and women who are equally attracted to same-sex and opposite-sex partners in the "gay-friendly" Netherlands (N = 389; 118 gay men, 40 bisexual men, 184 lesbian women, and 54 bisexual women). Results showed that minority stress is also related to mental health of Dutch LGBs. Participants with a higher level of internalized homonegativity and those who more often encountered negative reactions from other people on their same-sex sexual attraction reported more mental health problems. Such negative reactions from others, however, had a stronger link with mental health among lesbian/gay than among bisexual participants. Openness about one's sexual orientation was related to better mental health among sexual minority women, but not among their male counterparts. Suggestions for future research, implications for counseling, and other societal interventions are discussed. (Contains 3 tables, 2 figures and 1 footnote.)