An early approach to influencing was proposed by John Watson, and developed by B.F. Skinner. It is called operant conditioning and it seeks to encourage desirable behaviour while discouraging undesirable behaviour. It has been applied to many different aspects of life including the organizational context (Campbell et al., 1985; Huberman, 1964; Luthans and Martinko, 1987; Nord, 1970; Organizational Dynamics, 1973). Operant conditioning, or behaviour modification as it is more commonly known, is based on three assumptions. First, that what needs to be changed is not the individual, but some aspect of their behaviour. Second, that the person ultimately responsible for behaviour change is the person themselves. Third, your responsibility as the influencer is to bring the problem behaviour to their attention, get them to acknowledge that it is indeed causing difficulties, and assist them to modify it so that it becomes acceptable to all concerned. This chapter describes a set of procedures that are based on the principles of behaviour modification. For illustrative purposes, it will focus on the organizational situation of a manager influencing a subordinate.