This study employed descriptive survey research design in investigating the relationship among home background, social adjustment and Academic Achievement in biology of Senior Secondary School Students in Niger State, Nigeria. Five research questions and five hypotheses were formulated to guide this study. Three hundred and thirty-one (331) male and female students made up the sample of this study. Home background(parents educational level),Social Adjustment Scale (SAS) and Biology Achievement Test (BAT) were the instrument used for data collation. The data collected were analysed using t-test, ANOVA and PPMC (r). The findings of this study revealed that Significant relationship exists between Home background(parents educational level) and academic achievement of senior secondary school students.(r=.878,p=0.000), significant relationship existsbetween Social adjustment and Academic Achievement of senior secondary school students in Niger State (f = .544, p = 0.000), significant difference does not exist in the academic achievement level of male and female senior secondary school students in Niger State (t=0.244,p=0.002)significant differences exist in the Social adjustment level of male and female senior secondary school students in Niger state. (t=0.306,p=0.759), Significant relationship does not exist in the Social adjustment of students on the account of their Home background(parents educational level) (f = 0.685, p = 0.685).among senior secondary school students in Niger State. Based on the findings of this study, it was recommended that parents should create an environment that the children can express their opinion without hesitation and that both male and female students should be given equal opportunity to explore.