Practitioners are encouraged to apply theories of reading development to psychoeducational test interpretation. Orthographic mapping provides an explanation of the acquisition of sight words. Although many test batteries provide tasks for practitioners to assess reading components associated with orthographic mapping, the relationship among components will vary across batteries and specific task demands that can impact their interpretation by practitioners. This study evaluated the effects of phonemic awareness and oral language skills on various indicators of orthographic mapping competence while controlling for word decoding skills in the standardization samples of the Kaufman Tests of Educational Achievement, 3rd Edition (KTEA-3) and the Wechsler Individual Achievement Test, Fourth Edition (WIAT-4). The WIAT-4 phonemic awareness subtest's task demands and relationships between it and some measures of word reading conform to the phonemic proficiency hypothesis. We discuss implications for comprehensive psychoeducational assessment when evaluating student reading development.