This study explored pre-service teachers’ familiarity, interest, and conceptual understanding of science process skills. A sample comprised ninety one primary school pre-service teachers at a university in the Midwest of the USA. Participants were enrolled in two science education courses; introductory science teaching methods course and advanced science methods course. The introductory science methods course is mainly focused on developing science process skills among pre-service teachers while the advanced science methods course is focused on content and pedagogical knowledge. Data were collected through a questionnaire. Results showed that pre-service teachers had higher familiarity and interest levels in science process skills, but very poor conceptual understanding of the science process skills. Their incorrect definitions of science processes ranged from not having any idea to tautology. Moreover, most participants interchanged definitions of some science processes notably measuring and quantification; and predicting and inferring. The findings have implications for science teaching, learning and teacher education.