Although special education legal knowledge is central to educating students with disabilities, how two critical school professionals--special educators and school principals--garner such knowledge is unclear. This study identified gaps in the professional training for special educators and school principals by examining professional standards and common textbooks. After identifying 32 special education legal concepts, we used content analysis to determine the extent to which each concept was mentioned in professional standards and preservice textbooks (five in special education, six in principal preparation, and four in school law). Compared with special education textbooks (in which 68%-84% of special education legal concepts were mentioned), preservice principals received less information on special education law in their general textbooks (3%-13% of concepts mentioned), although gaps narrowed when examining school law textbooks (63%-81%). Special education and school law texts consistently included concepts related to the six pillars of the Individuals with Disabilities Education Improvement Act (IDEA), as well as more specific concepts, such as discipline/behavior and related services. Rarely mentioned concepts were extended school year, resolution meetings, and compensatory services. We discuss training, research, and policy implications.