In the local school district under study located in southern United States, English as second language (ESL) students are experiencing lower than expected standardized testing scores according to expectations set forth by the state Department of Education. The purpose of this project study was to explore the strategies ESL teachers use to teach ESL students. The conceptual framework was Gagne's conditions of learning theory, which is used to assess students' lack of preparation for future academic and career success. The research question asked what strategies ESL teachers use to teach ESL students. A qualitative exploratory case study with purposive sampling was used to select high school ESL teachers who taught ESL students. Data were collected through 10 semi structured interviews and 10 classroom observations. Data were analyzed using Hatch's nine-step typological process. The finding indicated that ESL teachers use specific strategies such as motivational reading, vocabulary, content scaffolding, and effective reading development strategies for ESL students to increase their proficiency in English. The key recommendation was a district-wide professional development for high school ESL teachers to learn how to support ESL students for these students to increase their proficiency in literacy. The implications for positive social change include teaching strategies for high school ESL teachers to use to strengthen ESL students' literacy skills for these students to be successful in the classroom and graduate from high school. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]