People need scientific literacy to keep up with and to understand continuing developments and changes in our modern world. In Turkey, especially for the people from low socioeconomic backgrounds, scientific literacy level tends to be low. The current study investigated how two environmental-literacy related factors contributed to the scientific literacy of students from different socioeconomic backgrounds. The study was based on the results from the PISA 2015 cycle. The PISA sample was composed of 5,859 15-year-olds randomly selected from 187 schools in different regions of Turkey. The relationships between environmental awareness and scientific literacy and between environmental optimism and scientific literacy were investigated using a multiple linear regression analysis technique. The difference in the environmental literacy and the environmental optimism level of the students from different socioeconomic levels was analyzed by using one-way ANOVA. Results revealed that both environmental awareness and environmental optimism were found to be significantly related to scientific literacy. Also, socioeconomic status created significant differences in environmental awareness and in environmental optimism among different socioeconomic levels. Finally, it was found that there is a significant relationship between scientific literacy and environmental awareness and between scientific literacy and environmental optimism for all socioeconomic levels.