Research shows the significance of the role of the principal, organizational management, and conditions of schools to improvements in instruction (Hallinger & Heck, 1997; Leithwood, Jantzi, & Steinbach, 1999; Newman & Wehlage, 1995; Purkey & Smith, 1983: Sergiovanni, 1996; Sheppard, 1995). School improvement research has shown that school leadership is the single most important factor to instructional improvement (Barth, 1986; Leithwood & Montgomery, 1982; NCSL, 2003). There is a strong link between the quality of school leadership and management, the key staff in a school and the quality of instruction (NCSL, 2003). The research on programs for English language learners (ELLs) show that the most successful programs are those programs with principal leadership, support, and knowledge of English language learners (Armendariz & Armendariz, 2000; Calderón & Carreon, 2000; Carter & Chatfield, 1986; Garcia, 2001; Gonzales, 1992; Montecel & Cortez, 2002; Sather, Katz, Henze, Walker, & Norte, 2001; Saville-Troike, 1984). School leadership and the role of the school principal are the most important variables associated with effective and successful schools, including those with successful programs for English language learning students (Lezotte, 2003). The purpose of this chapter is to examine the research on school leadership, the research on the effects of school leadership on successful programs for ELLs, the role of principal preparation, and to make recommendations on ways that principal preparation programs can prepare school leaders to be leaders for English language learners.