This study explored Taiwan citizens’ scientific literacy, interest in, and engagement in learning science. By using the stratified random sampling strategy, 1,831 citizens in the age group of 18-70 years were selected to respond to a questionnaire survey along with a paper-pencil test. For exploring the relationship between Taiwan citizens’ scientific literacy and their interest in science, the participants were divided into four groups on the basis of their scores for scientific literacy and interest in science. According to the essential results, the high scientific literacy and high science interest (HH) group was mainly represented by males, young citizens, and citizens with higher educational degrees. Conversely, the low scientific literacy and low science interest (LL) group was dominated by females, elderly citizens, and citizens with only a secondary school diploma. Among the four groups, citizens in the HH and LH groups exhibited higher frequency of engagement in science activities. Finally, citizens with high science interest tended to be enthusiastic in learning science and technology. This study contributed a novel insight that the interest in learning science plays a critical role in promoting adults’ engagement in learning science. Future studies are recommended for focusing on the citizens in the LH group to investigate how high engagement in learning science influences their scientific literacy.