International research has a plethora of findings which show that gender, sex characteristic, and sexuality diverse (GSSD) staff and students are discriminated against and treated as ‘unwelcome’ on tertiary campuses at higher rates than their cisgender, endosex, and heterosexual (cis-endo-hetero) counterparts. Further research has demonstrated that GSSD people have greater potential to thrive academically (specific to students) and personally when universities foster campus climates that are inclusive of their identities. In Aotearoa New Zealand, there is a dearth of literature about the experiences of GSSD people on university campuses. This thesis research was conducted to help address the knowledge gap. A community psychology and mixed methods approach was used in this study to understand GSSD staff and student perceptions of the campus climate at the University of Waikato, as well as to determine how to best achieve improvement, if needed. The first research stage included seven focus groups with GSSD staff and students, with initial analysis of the qualitative data collected from these focus groups being used to inform Stage Two: a campus climate survey. The survey was conducted with the intention to gain a broad range of views from university staff and students who identified as GSSD and as cis-endo-hetero (N = 343). GSSD participants largely described The University of Waikato as a heteronormative, endonormative, and cisnormative environment. Further analysis also brought to light the mononormativity experienced by GSSD people who are non-monogamous. Full analysis of Stage One data resulted in the finding of ‘the (in)visible self’, which refers to the ways in which participants made their GSSD identities visible or invisible in the campus space at different times for varying reasons, including for the sake of their wellbeing. Participants in the focus groups also expressed the need for the university to actively include and educate about GSSD identities on campus so that GSSD people can more safely be ‘visible’ as themselves. These Stage One findings were supported by the qualitative data generated from the Stage Two survey; however, GSSD people in the survey expressed an additional desire for their identities to not just be included and educated about, but to also be considered ‘normal’ at university. Of particular interest is that this notion of ‘normal’ did not incorporate homonormative or transnormative rhetoric. Overall, this research expands on the limited existing literature in Aotearoa New Zealand to demonstrate there is a local need for universities to critically re-examine their practices, policies, and educational content in relation to gender, sex characteristics, and sexuality, with this thesis identifying the most promising intervention options, according to participants. People with a range of GSSD voices should be included in any intervention efforts (rather than GSSD people being treated like a homogenous group). Having GSSD voices included in any interventions is also important given my thesis research found that cis- endo-hetero people overestimated the acceptance of some GSSD groups on campus (e.g., non-binary people, bisexual and pansexual people) compared to the perceptions of GSSD participants themselves. The thorough disruption of heteronormative, endonormative, and cisnormative discourses on campus would create a climate in which being GSSD is considered normal (i.e., not remarkable, or forcibly [in]visible) and cisgender, endosex, and heterosexual identities are not normative (i.e., perceived as what should be normal) in university policy, educational content, and everyday interactions.