Lesbian, gay, bisexual, and transgender (LGBT) persons face important health issues relevant to dermatologists. Men who have sex with men (MSM) are at higher risk of certain infectious diseases, including HIV, syphilis and other sexually transmitted diseases (STDs), methicillinresistant Staphylococcus aureus infections, and invasive meningococcal disease, and might be at higher risk of non-infectious conditions, including skin cancer. Recommendations for preventive health care, including screening for HIV and other STDs, sexual health-related vaccinations, and HIV pre-exposure prophylaxis, differ for MSM compared with non-MSM. Women who have sex with women experience disparities in STDs, including chlamydia and HPV. Transgender patients have unique, and often unmet, dermatologic needs during gender transition (also called gender affirmation), related to hormonal therapy and gender-affirming surgery. Familiarity with LGBT health issues and disease-prevention guidelines can enable dermatologists to provide medically appropriate and culturally competent care to LGBT persons.