This is a dissertation on The Effect of Problem-Based Learning Strategy on Higher Cognitive Skills Performance in Biology at Secondary School Level. A total of eight-hundred and ten (810)SSS2 students from four schools were used. Instruments for data collection were teacher-made achievement test and questionnaire.It was an experimental study that involved the Solomon four-group design. Through the SPSS software, t-test was used to calculate the differences between two means. Six hypotheses were formulated and tested. The significance level was set at alpha 0.05 and this determined the...