Factors that influence and predict academic success of ESL students were studied to assist the Ministry with decisions related to curriculum development, resource allocation, and support provision. The comprehensive nature of this study is unique in that it presents the state of affairs of K-12 ESL education in Alberta. Best practice information is drawn from principals and teachers at various grade levels and geographic locations across the province. Views of experts and other stakeholders and research evidence have been considered in light of longitudinal data on ESL student achievement. Finally, a synthesis of findings has culminated in identification of factors and predictors of academic achievement of ESL students and a set of recommendations is offered to develop an action plan. Both qualitative and quantitative methodologies were used to conduct this study, including a comprehensive literature review. Eight case studies examined current practices related to funding, assessment, program delivery, completion of Provincial Achievement Tests and Diploma Exams, influencers on social adjustment of ESL students, facilitators and barriers to implementing best practices, early leaving, leadership, and recommendations for priority action. Semi-structured interviews were conducted with 47 stakeholder/experts, and a province-wide survey of principals and teachers was used to gather descriptive information on current practices. In light of the findings, the consultant recommended that Alberta Education re-examine the current funding structure for K-12 ESL, that a recommended list of diagnostic and assessment instruments be used, that ESL proficiency standards and guidelines for instructions strategies be articulated, that sufficient support and time to learn English and subject matter contents is allowed, that provision is made for more professional development opportunities for practicing teachers and teacher assistants, that there are opportunities for inclusion of ESL related courses in teacher education and student teacher placements, that a research agenda is developed to address priority questions and issues in ESL education and, that transition options for ESL students to complete High school requirements are explored. Appendices include an extensive literature review (2005) and a bibliography. [This document was prepared by Howard Research & Management Consulting Inc. and was published by Alberta Education.]