Traditional ecological knowledge (TEK) is knowledge of indigenous people's best practices in contact with nature gained through centuries of experience. One way to transmit the experiences is folktales about corn and vegetable planting in Tawangmangu Sub-district, Central Java, Indonesia. Today, young generations do not recognize the folktales and thus do not understand the important values implied in the stories about non-rice food security. This condition triggers the importance of literacy of folktales among local students. This study aims at investigating the effects of folktale-based comics on the level of students' mastery of TEK through quasi-experimental research. The population in this study includes fifth-grade elementary students in Tawangmangu. The experimental group was given treatment with folktale-based comics, while the control group received treatment with texts. The instrument used to measure the students' literacy level of TEK was a multiple-choice test with 38 items. The results have proven the significant contribution of folktale-based comics to the students' mastery of TEK, indicated by the large category of the Cohen test. Therefore, teachers are recommended to take advantage of educational comics to improve students' literacy in the local cultural wealth that is becoming extinct.