Despite growing evidence for learning loss due to COVID-19, there is little research examining this phenomenon using norm-referenced tests (NRTs) or with special educations students. Using a repeated-measures design with 96 fourth- through 12th-grade students previously identified as eligible for special education services, the present study attempted to measure learning loss using W Difference scores gathered from triennial evaluations using the Woodcock-Johnson IV Tests of Achievement. Findings revealed that participants fell further behind proficiency expectations in the areas of decoding, spelling, and math calculation skills. Academic proficiency was found to differ markedly from normative expectations for typical same-age peers across tests, both prior to and during the COVID-19 pandemic. While academic proficiency was more like that of a clinical sample of students with learning disabilities, moderate to large differences in the sample means of most tests suggest that COVID-19 has had a negative impact on academic achievement.