This study focuses on fostering students' cognitive achievement using students-concept maps and demonstration in chemistry. A pre-test, post-test control groups 3 x 3 x 2 factorial design was employed. A total of two hundred and forty eight senior secondary two students drawn from three public secondary schools in Ogun state of Nigeria participated in the study. Stratified random sampling technique was used in drawing the schools. Intact classes of students were used for the study. Three research questions and three hypotheses guided the study. Treatment that lasted for four weeks involved teaching redox reaction concepts to experimental groups using students-directed concept mapping, demonstration while the control group was taught using lecture method. Test of Knowledge in Redox Reaction (TKRR) was the instrument for data collection. Mean and standard deviation were used to answer the research questions while the hypotheses were tested with Analysis of covariance (ANCOVA). Results revealed that there was significant difference in the cognitive achievement of students taught using students-directed concept mapping, demonstration and lecture method. Experimental groups' achievement was significantly better than those taught using lecture method. Also ability level is significant factor on students' cognitive achievement in Redox reaction. However, no significant difference was found on the effect of gender on cognitive achievement. Based on the findings, the use of students-directed concept mapping and demonstration strategies to foster cognitive achievement in difficult concept like Redox reaction in chemistry was recommended to chemistry teachers.