This article explores the beliefs regarding the causes of change and no-change of substance-using clients during motivational interviewing (MI) sessions in probation service context. The analyses are based on videotaped and transcribed data consisting of 98 MI sessions in 12 probation service offices in Finland from 2007 to 2009. The analysis relies on coding of client’s change-related talk utterances and qualitative semiotic framework. The results show that the clients attributed various causes to change and no-change. It seems that the sociocultural, psychological, biological, and contextual causes play an important role in substance users’ change talk and motivation to change. It is suggested that aspects of the social and contextual factors should not be overlooked in MI and other substance use treatment.