This study investigated the Effect of Project-based Approach on Acquisition of Entrepreneurial Skills, Retention and Performance in Biology, among Secondary School Students, in Niger State, Nigeria. The study adopted pre-test, post-test, quasi-experimental design. The population consisted of 149,290 public senior secondary school students in the state. Three secondary schools were purposively sampled from the seven educational zones in the state. The sample size was 150(75 male 75 female) SSII Biology students assigned to three groups (two Experimental groups (EG1&EG2) and one Control Group (CG)} with 50 subjects per each group. Three instruments (1) Biology Concept Entrepreneurship Test (BCET), (2) Entrepreneurial Skill Acquisition Test (ESAT) and (3) Biology Achievement Test (BAT)were used in collecting data after validation. The reliability coefficients of the instruments using PPMCC were estimated at r = 0.71, r = 0.78 and r = 0.68 respectively. Results from this study provided answers to six stated research questions using descriptive statistics in form of mean, standard deviation and standard error. Hypotheses testing were carried out using t-test, Scheffe test, ANOVA and ANCOVA at P<0.05 level of significance. One among the hypotheses states that there is no significant difference in students' performance means scores when exposed to Project-based Approach and their counterparts taught using Lecture Method. ANOVA and Scheffe test were conducted to identify the cause of the significant difference. One of the findings revealed that there was significant difference in performance mean scores of students taught biology concepts for entrepreneurship using Project-based Approach. There is significant difference in students' ability levels in skills acquisition using DATS as assessment tool over those exposed to TFLE as assessment tools of Project-based Approach in biology. Based on the findings recommendations were made one of which was, a common curriculum should be developed to maximise students' retention and performance in acquisition of meaningful knowledge and skills in biology through Project-based Approach.