The main objective of this study was to investigate developmental change of gender knowledgernand gender typed beliefs (gender stereotype) between purposely selected single sex and mixed sexrnschool children. To this end ,the relationship between age, sex, gender knowledge and genderrnstereotype and the difference on gender knowledge and gender stereotype were examined in fivernand six year old boys and girls. Data were obtained from 162 children and their parents (i. e., 81rnfrom mixed and 81 from single sex school children). Quantitative methods were used to obtainrndata, analyzed and discuss the findings. Major findings showed that the predictor variable agernhas relationship with the out come variable gender knowledge and gender stereotype. It was alsornfound that five year aids displayed lower level of gender knowledge level than six year aids. Thisrnwas truefor both sexes. Boys and girls were not differing in knowledge of gender because of theirrnsex. The result also showed that six year aids displayed higher awareness of gender stereotypernthan five year aids. In addition to this, it was also found that female school children displayedrnlesser on gender stereotype than mixed sex children and male single sex school their meanrndifference were, with mixed sex school children =-2.07 and with male single sex school childrenrn=-1 .2951. Children's gender knowledge and gender stereotype was also varied do to theirrnparent's gender rule attitude and educational level .The analyses of the result shows thatrnchildren from modern mothers and fathers displayed a lesser amount of knowledge of gender andrngender stereotype .Similarly children from higher educated parents were showed less awarenessrnin gender and gender stereotype than children from illiterate and primary education parents.rnTo sum up, since the present only shows the variation of children in their understanding ofrngender and gender stereotype it is advisable making further reserved on the area and on whichrnthis study doesn't teach to fill the gap.