The effectiveness of behavioral intervention programs can be assessed by measuring changes in behavior using reliable and valid instruments. To our knowledge, a reliable instrument designed to measure changes in psychosocial determinants of whole-grain intake by children due to an intervention does not exist in the literature. This article describes the development and testing of two questionnaires designed to measure psychosocial determinants of whole-grain intake among children and their parents. The questionnaires were pilot-tested with 39 parent/child pairs from one school and subsequently used in an intervention program with 150 parent/child pairs from two schools. Internal consistencies for the child and parent scales were modest (α=.41 to .63), with the exception of intention to choose whole-grain foods for children, which was low (α=.19). Test-retest reliability of the child and parent scales was acceptable (r=0.58 to 0.90). Principal components analysis confirmed three parenting subscales: enabling behaviors, whole grain health benefits, and role modeling. Identification of whole-grain foods remains a substantial barrier to the development of a questionnaire that accurately measures psychosocial determinants related to whole-grain intake. Future work should focus on instrument development and testing on a broader scale.