The problem is that Dominican student immigrants enrolling in Puerto Rican high schools need to be English proficient and the English as second language program (ESL) is not effectively supporting these students to develop English proficiency to graduate from the target high school. The purpose of this qualitative case study was to understand the perceptions of Dominican immigrant ESL students regarding motivators and demotivators in ESL classes to develop English proficiency at the target site. Using Krashen's conceptual framework, students' perceptions of motivators and demotivators regarding ESL classes, and their suggestions for improving the ESL instruction were explored. A qualitative case study design, using purposeful sampling was used to collect data through semi structured one-on-one interviews from 8 ESL students who met the criteria of being a Dominican ESL student and being 18 years or older. Data were analyzed using ATLAS.ti 7. The findings indicated more time and instructional support was needed for ESL students to develop English proficiency and targeted professional development was needed for the ESL teachers. Themes emerging from the findings were that ESL teachers should (a) use motivators and specific instructional strategies, (b) be aware of demotivators, and that (c) additional instructional time was needed to improve students' English proficiency. A white paper with recommendations to improve ESL instruction developed to present to district stakeholders. The adoption of these recommendations will result in social change by strengthening ESL students' English and literacy support, leading to ESL students' academic success, high school graduation and opportunities to attend college or join the workforce. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]