Sugar-sweetened beverage (SSB) consumption may increase risk for unnecessary weight gain. To develop interventions discouraging consumption, more insight is needed about cognitive and environmental predictors related to the decrease in SSB consumption. The present paper aims (1) to describe the relationship between potential cognitive determinants of change (attitudes, subjective norms, perceived behavioural control and intentions) and perceived environmental factors (family food rule and home availability of SSB) with changes in SSB consumption between baseline and 4-month follow-up and (2) to study whether the relationships between the environmental factors and SSB consumption are mediated by the cognitive determinants. Information on possible predictors and SSB intake at baseline and 4-month follow-up was provided by 348 Dutch adolescents (aged 12–13 years) through online questionnaires that were completed at school. Multilevel logistic regression and mediation analyses were used to determine direct and indirect associations between predictors and behaviour. The present results show that a high perceived behavioural control to decrease intake at baseline was associated with a decrease in consumption of SSB between baseline and follow-up (OR = 0·53). Low availability and a stricter family food rule were associated with a decrease in SSB consumption between baseline and follow-up (OR = 2·39, 0·54). The association between availability and decrease in SSB consumption was for 68 % mediated by perceived behavioural control to drink less. In conclusion, interventions to decrease SSB intake should focus on improving attitudes and perceived behavioural control to reduce intake, and on limiting home availability and stimulating stricter family food rules regarding SSB consumption.