In 1938, the British enacted Section 377A of the Straits Settlements Penal Code, criminalizing male same-sex acts in Singapore. Although the law was neither the first nor only attempt to regulate same-sex activity, it represented a stark intensification in sexual policing. Yet, the reasons for the introduction of Section 377A remain elusive. New sources, including recently declassified documents, reveal that Section 377A intersected with the colonial state's wider project of social control. In the early 1930s, intensified policing of female prostitution inadvertently magnified the visibility of male prostitution in Singapore, just as homosexuality was emerging as a distinct conceptual category. Meanwhile, scandals about sexual liaisons between European officials and Asians men threatened British legitimacy. This “discovery” of homosexuality led the British to introduce Section 377A. As British troops arrived in Singapore in the late 1930s in response to Japanese expansionism in the Far East, concerns about blackmail, military discipline, and the colonial color line governed the enforcement of Section 377A. Between 1938 and 1941, the British disproportionately used Section 377A to punish Asian male prostitutes whom they thought had seduced European men. Secondarily, the British used the provision to deter European soldiers, sailors, and non-officials from exposing themselves to extortion. Seen in this light, Section 377A served as a response to changing configurations of race, class, and sexuality in colonial Singapore.