This chapter describes colonialism in the British Empire, also in the light of its European background, and surveys the substantial long-term consequences this has had, both socio-politically and structurally, for the English language and our conception of it: English is no longer a monolithic language but a set of “Englishes”, related but distinct varieties. It highlights the political and social motivations for colonial expansion and explains the ultimate success of British colonialism as opposed to that practised by other European powers. Different types of colonization strategies produced different linguistic outcomes. Settlement colonization, marked by large-scale population migration, resulted in dialect contact and new dialect formation via koinéization. Exploitation colonization caused increased language contact, processes of structural nativization, and the emergence of “New Englishes” in “ESL” (English as a Second Language) countries, as described fundamentally in the “Dynamic Model” of the evolution of Postcolonial Englishes and found generally across Asia and Africa today. Heavy contact, especially in plantation settings, has produced pidgins and creoles, notably in the Caribbean. These processes have generated characteristic structural properties of “World Englishes” as well as typical social outcomes (e.g. language attitudes and decisions in language policy).