Students' motivation in reading at a young age may have significant influence on later learning outcomes. However, there is a dearth of instruments that measure elementary students' reading motivation, making it difficult for research advancement in the study of reading motivation. A multidimensional Reading Motivation Questionnaire (RMQ) was developed to investigate the reading goal orientations of students from Kindergarten to 6th grade (N = 275 from an independent girls' school). Confirmatory factor analysis found five clearly distinguishable factors: Mastery, Intrinsic, Cooperative, Individual, and Competition. The youngest students (K-2nd grade) were less able to differentiate the factors than older students (3rd-6th grade). The oldest students showed the greatest differentiation between the Individual and Cooperative factors. There was a decline found in four of the factors with age. The exception was the Individual factor, which was lowest for the youngest students. The instrument provides researchers and educators with a valid instrument to assess the motivational goals of elementary students, examine their development, and devise teaching and learning strategies based on theory and evidence.