This chapter consider translating and interpreting as sociolinguistic activities. Any language mediation occurs as part of normative social practices and is dictated by language behavioural rules that continuously evolve, whether the agents in the communication are present (interpreting) or meet through the mediation (translation). The chapter starts by considering historical perspectives on the interaction between early translation and interpreting scholarship and concepts from sociolinguistics. With a common focus on how social and linguistic factors influence communication and organize meaning, high-level concerns of sociolinguistics also represent a practical and immediate priority for any language and culture mediator. Few processes are as concerned as translation and interpreting are with register, channel of communication, tenor, field, function of the message, and social relationships between interactants, and the chapter reflects on the influence of sociolinguistic concepts on approaches to translation and interpreting, which have become prominent in research in Translation and Interpreting Studies. The chapter reviews debates focused on topics that demonstrate the interrelationship between the two disciplines, and new perspectives on translation and interpreting emerging in sociolinguistic scholarship. As translators and interpreters operate in ever more technologically competitive contexts, in which social interactions occur in mixed modes and on a number of physical and virtual platforms, the chapter suggests that a competent grasp of sociolinguistic concepts is likely to remain an intrinsic part of the skillsets of translators and interpreters.