This qualitative case study explores how the LGBTQ+ community is included in informal STEM learning environments (ISLEs) such as museums and science centers. One science center was chosen as a case study to identify how ISLEs may broaden participation to the LGBTQ+ community, how institutional stance impacts LGBTQ+ community members, and how the systemic power structures of ISLEs affect inclusive practices. Through semi-structured interviews, exhibit and signage audits, and document analyses, the researcher examines how practices and policies welcome or exclude diverse identities in informal STEM education (ISE) by adapting Dawson's (2014a) equity and access framework. Findings from this analysis include a need to remove barriers to broaden LGBTQ+ participation; to implement policies and procedures to improve institutional stance towards the LGBTQ+ community; to increase queer representation in ISLEs; and to acknowledge LGBTQ+ individuals as agents of social change. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]