This study examined the effect of journal writing on mathematics achievement in high-ability students in Singapore. It assessed both the cognitive benefits of journal writing (as evidenced through gains in math test scores) and the socio-affective benefits of journal writing (as demonstrated in their personal reflections) as the students learned algebra. Fifty-four 13-year-old boys from two Secondary One classes in Singapore (Control and Experimental groups) participated in the study over a six-week period. A t-test (p = 0.05) was conducted to demonstrate the changes in the Control and Treatment group's mathematical test scores as a result of journal writing. An online questionnaire was also administered to obtain descriptive data regarding students' attitudes towards and difficulties in the implementation of the journal writing exercise. Results revealed that journal writing has a significantly positive effect both on gifted students' mathematics performance "and" their attitudes and dispositions towards mathematics learning. Implications are discussed for gifted education practices, especially in mathematics.