This study examined how children's and adolescents' with Type 1 diabetes mellitusglucose levels during and prior to academic assessment contributed to performance on reading, writing, and mathematics tasks. Participants had a mean age of 13.69 (SD = 2.10); 44.6% were female and 58.1% reported their ethnicity to be Hispanic, Latino, or Mexican. They wore a continuous glucose monitor for approximately 6 days and completed a neurobehavioral evaluation that consisted of tasks assessing basic reading skills, reading fluency, reading comprehension, math fact fluency, math calculation, spelling, and writing fluency. Results indicated that individuals whose glucose levels were suboptimal (>140 mg/dL) or hyperglycemic (>180 mg/dL) had significantly lower scores on reading fluency ([eta][subscript p, superscript 2] = 0.16) and writing fluency ([eta][subscript p, superscript 2] = 0.28) subtests than those in the target range (70-140 mg/dL). Moreover, more time spent hypoglycemic (<70 mg/dL) within the 12 hr prior to the evaluation increased the risk for impaired performance on academic tasks. These findings support the need to move beyond considering only overall glycemic control to review temporal influences of glucose levels on academic performance. By tracking how fluctuations impact academic performance, school based practitioners can better determine necessary accommodations to buffer glycemic dysregulation effects. In particular, individuals whose glucose levels are frequently outside of the target range are at greatest risk for performing below their true academic potential.