This study focuses on the strength of the relationship between behavioural intentions and actual behaviour in a multi-alternative choice context. Two separate moderating processes of intention-behaviour consistency were hypothesized, i.e. the amount of reasoning during intention formation, and the degree of confidence in the intention. Involvement (as an issue-specific factor), and need for cognition (as an individual difference factor) were investigated as antecedents of amount of reasoning. confidence in the intention was predicted from the size of the consideration set (i.e. the number of alternatives that one considers for choice), and involvement. The study comprised a longitudinal two-wave survey conducted before and after national elections in The Netherlands, in which pre-election voting intentions were compared with actual voting behaviour. A high degree of intention-behaviour consistency was found, which was significantly related to both amount of reasoning and confidence. The expected relations were found. The results extend current process models of attitude–behaviour relations. Furthermore, the results indicate that processes related to the consideration set size and content account for variance in intention-behaviour consistency in choice contexts that cannot be accounted for by traditional attitude-behaviour perspectives.