Findings related to the adjustment of typically-developing (TD) siblings of children with Autism Spectrum Disorder (ASD) have been inconsistent, but suggest that most function well over time. The current mixed methods study investigated the relationship between family factors, especially disruptions to family routines, and academic functioning of TD siblings. Measures of family functioning, parenting stress, and parenting daily hassles were collected from parents (n = 20); an additional 19 families also completed semi-structured interviews (total n = 39). Teacher reports on classroom functioning (n = 25) and report cards were also collected. All parent participants (92% Caucasian, 90% married, 79% college-educated) had a child with an ASD diagnosis (80% male, M age = 11.74) and a TD child (62% male, M age = 10.31 years). Seventy-two percent of TD siblings (n = 18) had scores above the mean on the Academic Performance Rating Scale (DuPaul, Rapport, and Perriello, 1991), and 91% (n = 32) had grade averages of B or higher. Ninety-six percent (n = 24) of TD siblings had scores within the normative range on the Learning Problems and School Problems scales of the Behavior Assessment System for Children, Second Edition (BASC-2; Reynolds and Kamphaus, 2004). Daily hassles were not significantly correlated with any school measures for the TD siblings. Families with children with more severe ASD symptoms discussed greater frequencies of emotional outbursts in the child with ASD and missed social opportunities as a family. Families of children with externalizing behaviors may particularly benefit from targeted support.