Mobile phones are increasingly being associated with negative psychological constructs such as depression. Some researchers have suggested that excessive mobile phone involvement is a behavioural addiction, with similarities to substance addiction. It is suggested that an aspect of addiction is automatic and inflexible thought patterns relating to the addictive behaviour. It is proposed that a greater flexibility of thought patterns can be achieved with a hypnosis intervention, as hypnosis has been shown to override automatic thought processes. The aim of this study is to determine if a brief hypnosis intervention can reduce mobile phone involvement, and to investigate the relationship between this reduction and hypnotizability. Participants were asked to take part in an intervention session to assess their current mobile phone involvement using the mobile phone involvement questionnaire (MPIQ). They were also assessed for hypnotizability using the Sussex-Waterloo scale of hypnotizability (SWASH) and had post hypnotic suggestions delivered to reduce mobile phone involvement. The participants were asked to repeat the MPIQ online 10 days after the intervention. A paired t-test demonstrated that there was a significant reduction in mobile phone involvement after the intervention with a medium effect size. A Pearson correlation analysis of the data also showed that there is a significant positive relationship between hypnotizability and change in mobile phone involvement, this relationship had a medium effect size. These results could lead to future research on hypnosis being a viable intervention for behavioural addictions, which in turn could lead to a more effective treatment for the disorder.