A study investigated the effects of sex and grade in school on students' reading proficiency, students' beliefs about their reading, parents' beliefs about the students' reading, and teacher's beliefs about the students' reading. The study also examined causal relationships between student, parent, and teacher beliefs and students' reading proficiency. The subjects, 552 students in grades 3, 6, and 9 from very low income families in rural eastern Newfoundland (Canada), their teachers, and their parents. Students' reading comprehension was measured, and interviews were conducted with students, teachers, and parents. Results indicated that: (1) at each grade level, students had low mean scores on the standardized reading comprehension test, but their performance on teacher assigned grade was quite high; (2) at all grade levels, students and their parents had very positive beliefs about the students' reading, with teachers' beliefs considerably less optimistic; (3) female students had higher standardized test scores and higher teacher assigned grades than males; (4) compared to males, female students and their parents and teachers had much more positive beliefs about reading; (5) younger children held more positive beliefs about reading than older students; (6) at every grade level, students' beliefs about reading influenced their reading performance directly and significantly; and (7) students' beliefs were heavily influenced by the beliefs of their teachers and especially their parents. (Ten tables and six figures of data are included; 16 references are attached.) (RS)