Individual behavioural support for smoking cessation is effective but little is known about the 'active ingredients'. As a first step to establishing this, it is essential to have a consistent terminology for specifying intervention content. This study aimed to develop for the first time a reliable taxonomy of behaviour change techniques (BCTs) used within individual behavioural support for smoking cessation. Two source documents describing recommended practice were identified and analysed by two coders into component BCTs. The resulting taxonomy of BCTs was applied to 43 treatment manuals obtained from the English Stop Smoking Services (SSSs). In the first 28 of these, pairs of coders applied the taxonomy independently and inter-coder reliability was assessed. The BCTs were also categorised by two coders according to their main function and inter-coder reliability for this was assessed. Forty-three BCTs were identified which could be classified into four functions: 1) directly addressing motivation e.g. providing rewards contingent on abstinence, 2) maximising self-regulatory capacity or skills e.g. facilitating barrier identification and problem solving, 3) promoting adjuvant activities e.g. advising on stop-smoking medication, and 4) supporting other BCTs e.g. building general rapport. Percentage agreement in identifying BCTs and of categorising BCTs into their functions ranged from 86% to 95% and discrepancies were readily resolved through discussion. It is possible to develop a reliable taxonomy of BCTs used in behavioural support for smoking cessation which can provide a starting point for investigating the association between intervention content and outcome and can form a basis for determining competences required to undertake the role of stop smoking specialist. Copyright © 2010 Elsevier B.V. All rights reserved.