This study explores the effects of journal writing on students' ability to explain mathematical concepts and to surface attitudes towards the learning of mathematics. Journal writing is used in this Mathematics classroom to provide students with further opportunity to explain concepts and apply knowledge. Additional journal prompts were designed to provide the teacher with information on the students' attitudes in learning Mathematics. In this study, a Secondary One Express class (N = 37) completed six journal writing tasks over a period of ten weeks. Data on students' ability to explain concepts was gathered through the responses to the journal prompts. A pre and post journal writing comparison was made. Likewise, students' affective engagement before and after journal writing was compared. Students' views on journal writing was also gathered. Results suggested that journal writing had a positive impact on students' ability to explain mathematical concepts for the average ability pupils. In addition, it did have a great impact in their affective engagement towards mathematics. Students' responses to the survey indicated that journal writing is useful form of communication between teacher and students. The results of the study suggested that journal writing is a plausible alternative assessment mode for the average ability students of this neighbourhood secondary school in enhancing their ability to explain mathematical concepts.