PhD thesis introductions help student writers to discuss the significance of their study and establish how their study relates to and draws on previous research. The present study used a genre-based approach to examine one subsection in introductions of applied linguistics PhD theses. To that end, Iranian PhD thesis introductions were textually analysed. A researcher-made questionnaire, grounded on the responses from a semi-structured interview, was administered to Iranian applied linguists and PhD students to seek their opinions regarding how the subsection should be written. Frequency counts and statistical tests were used to analyse the data using SPSS (version 22). Results of genre analysis showed varying lengths, non-alphabetic ordering of the terms, and frequent uses of indirect quotations to organise the subsection. Results of textual analysis also revealed significant overlap between the terms in introductions and keywords in abstracts. The terms primarily derived from research questions. Results of questionnaire response analyses showed no statistically significant differences between the attitudes of applied linguists and PhD students. Implications of the study for PhD introduction thesis writing are discussed.