This study, students' perceptions of the image of a scientist in the enhancement of achievement in senior school Biology, was carried out using survey research design in Ogbia and Yenagoa Local Government Areas of Bayelsa State. Four research questions and three null hypotheses were posted. The population of the study was 12,315 Senior School Three Biology students. The sample of the study was 2,400 Senior School Three Biology Students. A purposive sampling technique was used to obtain the sample of the study. Two validated and reliable instruments, Perception of the Image of a Scientist Task and Students' School Promotion Examination Results Sheet, were used to collect data for this study. Data were analyzed using mean, standard deviation, frequency and z-test. The results were that more Senior School Three Biology Students perceived that a scientist is a male than those who perceived a scientist as a female. The female students who perceived that a scientist is a male were more than their female counterparts who perceived that scientist is a female. The researcher recommended, among others, that more female students should be encouraged to study science, including Biology and related courses to disabuse the perception that more males than females are scientists; science teachers should teach the students history and contributions of scientists to concepts in science and development of the society.