Special education certification is used as an indicator of teaching quality in research, practice, and policy. This study examined whether elementary and middle school students with learning disabilities (LD) or emotional/behavioral disorders (EBD) scored better on state math and English language arts (ELA) assessments in years when they were taught by a teacher certified in special education or dual-certified in special education and another area compared to years when they were taught by general education--certified teachers. For most student groups, academic achievement appeared unrelated to teacher certification type. Students with LD and higher academic skills appeared to benefit from having a dual-certified teacher over a general education--certified teacher in ELA. Lower achieving students with EBD scored worse in math when they were taught by special education--certified teachers instead of general education--certified or dual-certified teachers. Implications for indicators of teaching quality in special education are discussed.