This textbook introduces students to the ways in which techniques from corpus linguistics can be used to aid sociolinguistic research. Corpus linguistics shares with variationist sociolinguistics a quantitative approach to the study of variation or differences between populations. It may also complement qualitative traditions of enquiry such as interactional sociolinguistics. This text covers a range of different topics within sociolinguistics: *Analysing demographic variation *Comparing language use across different cultures *Examining language change over time *Studying transcripts of spoken interactions *Identifying attitudes or discourses. Written for undergraduate and postgraduate students of sociolinguistics, or corpus linguists who wish to use corpora to study social phenomena, this textbook examines how corpora can be drawn on to investigate synchronic variation, diachronic change and the construction of discourses. It refers to several classic corpus-based studies as well as the author's own research. Original analyses of a number of corpora including the British National Corpus, the Survey of English Dialects and the Brown family of corpora are complemented by a new corpus of written British English collected around 2006 for the purposes of writing the book. Techniques of analysis like concordancing, keywords and collocations are discussed, along with corpus annotation and statistical procedures such as chi-squared tests and clustering. Paul Baker takes a critical approach to using corpora in sociolinguistics, outlining the limitations of the approach as well as its advantages.