School psychologists have an ethical obligation to be advocates for students. However, the ethical principles of the National Association of School Psychologists (NASP) do not define what it means for school psychologists to be advocates for students, except through the inferences that may be drawn from what school psychologists must be, and do, in order to comply with the NASP ethical principles. This dissertation proposed a definition of advocacy, which was then presented to a focus group of school psychology experts, to an expert panel, and then researched through a census survey of the Colorado Society of School Psychologists (CSSP), preceded by cognitive interviews and a small pilot study. This dissertation explored the perceptions of CSSP members regarding their ethical obligation to be advocates for students, including students entitled to a free appropriate public education (FAPE) under the Individuals With Disabilities Education Act (IDEA). Survey respondents were queried to determine their responses to the researcher's proposed definition of advocacy; how prepared they believed they were to be advocates for students, including students with disabilities; the circumstances within which the need for advocacy was presented; the capabilities necessary to be advocates; and the barriers and enablers of advocacy.There were strong majorities of agreement with the researcher's proposed definition of advocacy, with the qualification that some concerns were expressed over the meanings of "persuasive" and "ethical character." There were strong majorities of agreement that school psychologists needed more education in advocacy in order to be better prepared as advocates. There were strong majorities of agreement that school psychologists should advocate for students; but survey participants also found advocating for students to be more problematic when the circumstances of this advocacy brought students into potential conflict with school district financial concerns and with job security for the school psychologist. Survey participants generally thought that good collaborative skills were necessary capabilities for effective advocacy by school psychologists, but they were divided over whether the capability to be adversarial with school staff and parents was necessary for effective advocacy. Responses from survey participants also indicated that conflicts between multiple clients of the school psychologist may be potential barriers to effective advocacy for students, and hence better resolution of such conflicts might enable better advocacy for students.