This study examines science and non-science students' perceptions of the effects of Facebook on their ESL learning. A questionnaire was used to gather data from 631 university students in Malaysia. The findings suggest the science students' more positive views of Facebook for ESL learning compared to their non-Science counterparts, although the differences in percentages between the two groups are small. The science students perceived higher confidence and motivation to read, speak, and write in English, in online and offline environment, after being exposed to Facebook. The science students also indicated a higher level of English language proficiency compared to the non-science students, which may explain their better perceived confidence and willingness to use Facebook in ESL environment. The incorporation of Facebook as a social media should therefore be seen as facilitating a variety of preferred learning styles and strategies in boosting students' learning interest, improving their language abilities, and providing them with the best academic experience.