The aim of this study was to delve into the effect of context-based approach (CBA) over traditional instruction (TI) on students' chemical literacy level related to thermochemical and thermodynamics concepts. Four eleventh-grade classes with 118 students in total taught by two teachers from a public high school in 2012 fall semester were enrolled in this particular study. The treatments were randomly assigned to the already formed classes; experimental groups were treated as CBA, the control groups as TI. Each teacher had one experimental and one control group. Open-ended contextual item sets were developed to assess students' chemical literacy level in thermochemical and thermodynamics concepts. The test was administered to both groups as a post-test at the end of the implementation. Students' responses to item sets were analyzed based on the rubric prepared as the answer key. Analysis of Covariance (ANCOVA) was used for interpreting the data. The results reveal that CBA is superior to TI on improving students' chemical literacy levels, implying that CBA, as a discussion platform for concepts through real-life experiences, has a significant role in increasing students' chemical literacy levels in abstract and difficult concepts regardless of the gender difference.