This study investigated the effect of personalized print-based instruction on the achievement and self-efficacy regarding mathematics word problems of 320 senior secondary students in Nigeria. The moderator effect of gender was also examined on independent variable (personalization) and dependent variables (mathematics word problem achievement and self-efficacy). The t-test statistic was used to analyse the data collected for the study. The results showed that significant differences existed in the mathematics word problem achievement and self-efficacy beliefs of personalized and non-personalized groups, male and female personalized groups and male and female non-personalized groups. (Contains 7 tables.)