This special issue integrates gender analysis into the global history of outdoor activities in the Age of Empire by focusing on masculinities, a field that has received renewed attention from scholars. The premise of the special issue is that social constructions of masculinities in imperial settings functioned twofold. They operated simultaneously as methods to spread Western-colonial hegemonic values and as a means to expand territorial domains into far-off lands. In examining outdoor experiences, without taking the dominance of ‘imperial’ men over non-Europeans for granted, the contributions here presented develop an intersectional understanding of the conditions in which fashioning and self-perception of masculine roles were constantly contested and negotiated. Outdoor experiences, as seen in this special issue, were formative spaces of empire: while made possible thanks to the wide imperial networks in the colonial world, they existed on the margins of imperial rule. At the ‘frontier’ and in colonial battle-grounds, but also as leisure or free-time activities in transcultural contexts, outdoor experiences served to transform boys into men, and for men to test and perform hegemonic ideas of manhood and hence of imperial power. The essays are in two sections that highlight the dual processes of being and becoming ‘manly’ in the imperial outdoors. The first four contributions focus on archetypical roles of adult men in empires: the mountaineer, the hunter, the sportsman and the soldier. The second section approaches cases of scouting as formative spaces for boys in contexts of decolonisation in the early 1900s. The case-studies included in this special issue cover multiple imperial formations from the American Midwest, the Middle East to the British and Dutch Indies. These diverse cases serve to open up often Anglo-centric historiographies of gender and empire by emphasising the global momentum of new masculinities that were embedded in a trans-imperial fashion between ca. 1860 and 1960.