Background There is some data regarding lesbian, gay, bisexual, and transgender (LGBT) cultural competency among healthcare professionals. While few studies have indicated differences in competency between heterosexual and sexual minority professionals, no known studies have assessed LGBT cultural competency among diverse groups with multiple minority identities. This study aimed to characterize healthcare professionals’ LGBT cultural competency by comparing twelve different demographically diverse healthcare professional groups based on gender identity, sexual orientation, and race. Methods Deidentified data (N = 2254) was aggregated from three independent studies (i.e., healthcare professional students, psychiatry residents, and dementia care providers). A series of multivariate analyses of covariance were conducted with groups (based on gender identity, sexual orientation, and race), other demographic variables as independent variables, and LGBT-Development of Clinical Skills Scale scores (Overall LGBT-DOCSS, Clinical Preparedness, Attitudinal Awareness, and Basic Knowledge) as dependent variables. Findings Compared to men, women reported significantly higher LGBT-DOCSS scores, except significantly lower Clinical Preparedness. Compared to cisgender, heterosexual professionals, cisgender, sexual minority professionals and gender minority professionals reported significantly higher LGBT-DOCSS scores. There were several other differences among groups, such as heterosexual, cisgender, White/Caucasian men reporting low LGBT-DOCSS scores but high Clinical Preparedness; heterosexual, cisgender, White/Caucasian women with high LGBT-DOCSS scores except Clinical Preparedness; heterosexual, racial minority professionals with low LGBT-DOCSS scores; and gender, sexual, and racial minority professionals with the highest LGBT-DOCSS scores. Conclusions There are subtle, yet important, differences in LGBT cultural competency among healthcare professionals. More diversity, intersectionality, and multiple minority identities appear to lead to higher competency. Appreciating these gender, sexual, and racial minority professionals’ unique perspectives may promote the development of better, more culturally affirming LGBT health education.