Abstract Background Launched in 2018, Time to Change Global is a new anti-stigma programme to tackle stigma and discrimination towards people with mental health problems in low- and middle-income countries. Our aim was to evaluate pre-post changes in stigma within the target populations for the social marketing campaigns ran in Ghana and Kenya carried out as components of the wider Time to Change Global programme. Methods Using data collected before and after each campaign in Accra and Nairobi, we investigated pre-post differences in stigma-related outcome measures: mental health-related knowledge (MAKS), mental health-related attitudes (CAMI), and desire for social distance (RIBS), with regression analyses. Other covariates were included in the models to control for differences in participant demographics. Results A significant positive change in a stigma related outcome was found at each site. Reported in standard deviation units, desire for social distance from people with mental health problems in Accra was lower after the launch of the campaign, measured as an increase in intended contact (β = 0.29, 95% CI = 0.14 to 0.43, p