The Commonwealth is the international governmental organization of states that emerged from the British empire, and since 2000 it has emerged as a focus for contestation relating to the regulation of same-sex sexualities, gender diversity, and diverse sex characteristics. Following colonial criminalizations focused on same-sex sexual acts, and later formal decolonizations, there have appeared many national movements for decriminalization and human rights in relation to sexuality and gender. The Commonwealth has emerged as a site of politics for some significant actors claiming human rights in relation to sexual orientation, gender identity and expression, and sex characteristics. This has been led by specific organizations of lesbian, gay, bisexual, and transgender (LGBT) people, increasingly with intersex people and allies, but it is also important to consider this in relation to queer people, understood more broadly here as people in all cultures experiencing forms of sexualities, biological sex and genders outside the social structure of heterosexuality, and its associated sex and gender binaries. A range of forms of activist and non-governmental organization (NGO) engagement have occurred, leading to shifts in Commonwealth civil society and among some state governments. This has required researchers to develop analyses across various scales, from local and national to international and transnational, to interpret institutions and movements. The British Empire criminalized same-sex sexual acts between males, and to a lesser extent between females, across its territories. In certain instances there were also forms of gender regulation, constraining life outside a gender binary. Such criminalization influenced some of those claiming LGBT human rights to engage the Commonwealth. Research shows that a majority of Commonwealth states continue to criminalize some adult consensual same-sex sexual activity. Yet the history of struggles for decriminalization and human rights within states in the Commonwealth has led up to such recent important decriminalizations as in India and Trinidad and Tobago in 2018. LGBT and queer activist engagements of the Commonwealth itself commenced in 2007 when Sexual Minorities Uganda and African allies demanded entry to the Commonwealth People’s Space during a Heads of Government meeting in Kampala. Activism has often focused on the biannual Heads of Government meetings that are accompanied by civil society forums. A particularly significant phenomenon has been the emergence of a “new London-based transnational politics of LGBT human rights,” evident in the creation from 2011 of new NGOs working internationally from the United Kingdom. Among these organizations was the Kaleidoscope Trust, which shaped the subsequent formation of The Commonwealth Equality Network as an international network of NGOs that became formally recognized by the Commonwealth. Significant developments occurred at the London Commonwealth Heads of Government meeting in April 2018; Prime Minister Theresa May expressed “regret” for past imperial criminalizations while announcing funding for Kaleidoscope Trust and other UK-based groups to use in international law reform work. These developments exemplify a wider problematic for both activists and analysts, concerning how LGBT and queer movements should engage in contexts that are still structured by imperial legacies and power relations associated with colonialism, persisting in the present.