Achievement in science had been declining in recent times. A number of reasons have been adduced for the poor achievement, among which is the teachers use of effective teaching methods. There is therefore a pressing need for continued researches aimed at developing more effective instructional strategies. This book looks at the effects of students interaction patterns (SIP) on cognitive achievement and interest in primary science. it explored the effect on the gender, and the combined effect of SIP and gender on the three criterion measures.It was hypothesized that; the SIP (cooperative, competitive and individualistic) teaching strategies will not have a significant effect on the students cognitive achievement and interest in primary science; gender will not be a significant factor on students cognitive achievement and interest in primary science; the combined effect of SIP and gender on cognitive achievement and interest in primary science will not differ significantly, due to students interaction patterns.