There are not many studies about affirmative competence and practices among mental health professionals working with Lesbian, Gay, and/or Bisexual (LGB) clients. Thus, the objectives of this research are to assess the levels of affirmative competence and practices of professionals in Ibero-American countries. The sample consists of 630 mental health professionals from various countries whose ages range from 22 to 75 years old, with a mean age of 41.46 years. The study utilizes the following measures: a socio-demographic questionnaire, the Sexual Orientation Counselor Competency Scale, and the Affirmative Practice Questionnaire. Results show that mental health professionals who present higher levels of Affirmative Competence are those who have higher levels of education and training on LGBT topics, show left-wing political affiliations, self-identify as LGB, and have no religious affiliations. Regarding Affirmative Practices, it was found that single participants show lower practices, and more studies are needed to better understand this result. Regression models demonstrate that Affirmative Practices and Competences are predicted by the hypothesized variables, namely, religious and political beliefs, and training/education. Hence, this study indicates that mental health professionals could undergo some type of academic or professional training and/or possess experience in regard to working with LGB clients, in order to enhance their approach when working with this population.