The aim of this study was to examine the effectiveness of science-technology-society (STS) approach based worksheets on improving Indonesian students' scientific literacy of 'environmental pollution' topic. Through quasi-experimental research method (nonequivalent pre-post control group design), the sample of the study comprised of 64 junior high school students in Lampung Province, Indonesia. The sample was assigned to two groups, namely experimental and control classes. An independent samples t-test and ANCOVA were rectruited to reveal any difference between the experimental and control groups' learning effectiveness and effect sizes. The results showed that the STS approach-based worksheets increased the students' scientific literacy levels. Given the values of n-Gain for the experimental (0.66) and control classes (0.48), the experimental class performed a higher value than the control one. The experimental group's eta square value was found to be p.[eta][superscript 2] = 0.767.