Background: Young people who have psychiatric problems are more likely than their peers to endure difficulties during their sexual and gender identity development. Aim: This study aims to examine the communication between mental health care providers and their patients about the topics of relations, sexuality and gender identity, including a description of professionals’ attitudes toward these topics and the factors that contribute to and inhibit communication. Methods: Study participants (n = 242, response rate = 31%) were a representative sample of a large multicenter cohort of 768 mental health care professionals (eg, medical doctors, psychiatrists, psychologists, group counselors, parent counselors) of 7 institutions and 5 solo practices in the Netherlands, who completed a survey on communication about sexuality and gender identity with their young patients (age 12–21 years). Outcomes: Sexuality and gender identity are infrequently discussed by mental health care providers with their young patients or their patients’ parents. Results: Of the study sample, 99.5 % valued sexuality as an important topic to discuss with their patients. However, only 17.1% of the professionals reported that they discussed sexuality-related issues with the majority (>75%) of their patients (adolescents: 19.9%, parents: 14.4%) Additionally, only 2.3 % of the participants discussed gender nonconformity regularly with patients. Information about sexual side effects of prescribed medication was infrequently (20.3%) provided: antidepressants (40.0%), antipsychotics (34.0%), benzodiazepines (5.1%) and stimulants (2.4%). The most frequently cited reasons for not discussing these topics were a lack of awareness, own feelings of discomfort, and the patients’ supposed feelings of shame. There was no gender differences observed. Clinical implications: Recommendations for professionals include to be aware of these topics, initiating age-appropriate conversation and use inclusive language. Strengths and limitations: The present study included a diverse and representative group of mental health care professionals. Frequency of sexual communication was based on self-report, which brings a risk of bias. Conclusion: Despite a recognized need to engage in age-appropriate communication about sexuality and gender identity in youth mental health care, mental health providers seem to remain hesitant to discuss such topics. Bungener SL, Post L, Berends I, et al. Talking About Sexuality With Youth: A Taboo in Psychiatry?. J Sex Med 2022;19:421–429.