Background Self stigma is assumed to be more prominent in Jordanian society than in Western countries, reflecting a poor understanding of mental illness, collectivistic culture, and delay in accessing psychiatric careAim The purpose of the study is to evaluate the effectiveness of a self-stigma reduction programme on self-stigma.Methods A randomized controlled trial was conducted from November 2017 to December 2018 with 278 people diagnosed with schizophrenia (PDwS). Participants were randomly assigned to receive a self-stigma reduction programme (psychoeducation, cognitive behavioural therapy and social skills training), or treatment as usual (TAU).Results PDwS in the intervention group experienced a greater reduction in the level of self-stigma (20.19 vs −0.62; p < 0.001) at post-intervention and (37.35 vs −0.66; p < 0.001) at six-month follow-up.Conclusions The findings suggest that the self-stigma reduction programme has the potential to reduce self-stigma levels. Trial registration NCT04087954