The main objective of this study was to find a range of dimensions of motivation structures that are manifest in highschool students and are independent of traditional structures of intrinsic, extrinsic, instrumental, and integrative motivations. For this study, 191 students responded to statements related to their English learning motivation in a Likert type scale. The statements were derived from personal observations of secondary school students by one of the researchers who categorized actions or attitudes towards their English learning. The subjects` responses to the questionnaire were submitted to SPSS version 17 for principal component factor analysis to understand the salient dimensions of motivation. The statistical results of the factor analysis revealed five dimensions: expectancy, compensation, interest, achievement, and goal congruency. The contribution of the five dimensions to reading proficiency scores was analyzed through logistic regression analysis. The findings of this study indicated that learning motivation held by students should be explored on the basis of students` perceptions of their own classroom realities.