The application of music in therapy is realised through different working modalities which can be categorised into three types of techniques: production, reception, and reproduction. These techniques are commonly used in mental health settings in music therapy practice and previous research suggests that specific working modalities might be important predictors of change in music therapy. However, little is known about which ingredients specifically contribute to the outcomes of music therapy. This study aimed to investigate the application of music therapy techniques and whether they predict changes in clinical outcomes in mental health settings with individuals displaying a low therapy motivation. Participants (N = 31) were assessed before, during, and after participating in individual music therapy. Music therapy techniques were assessed for three selected therapy sessions per participant. Associations between music therapy techniques and outcomes were calculated using linear models with repeated measures. Results showed that reproduction techniques were used most intensely. In addition, relational competencies (interpersonal and social skills) amongst the participants improved when focusing on reproducing music (e.g. singing or playing familiar songs, learning musical skills). Results indicated that reproduction music therapy techniques may foster the development of relational competencies in individuals with low motivation.