The French language can easily be regarded as the most important source of foreign influence in the history of English, especially if English lexis is considered. This chapter recounts the thousand years of English-French language contact and outlines the relevant contact-induced changes in English. A brief look at Central French, Anglo-Norman and Law French is followed by a discussion of the external history of contact situations involving English and French. The medieval insular phase receives the most attention, particularly the onset and early developments, with particular emphasis on questions of bilingualism, the length of the contact period, and the role of French as a superstratum language. The chapter subsequently presents an overview of the linguistic changes caused or motivated by contact with French: while the considerable growth of Middle and Modern English lexis due to lexical borrowing has often been explored, there are also changes observable on the other levels of language, perhaps less obvious and often more uncertain.