The COVID-19 lockdown and closure of schools clinics, and community-based services put children with autism spectrum disorders (ASDs) and other developmental disabilities (DDs) at increased risk of negative outcomes. This study aimed to investigate parents’ perceptions of their children’s behavioural outcomes during the COVID-19 lockdown, parents’ satisfaction with services during this time, and willingness to engage in telehealth. A cross-sectional study was conducted in Ireland. Parents (n = 89) completed an online questionnaire that included the strengths and difficulties questionnaire (SDQ-P). Results demonstrated that children with ASD/DDs were vulnerable to negative outcomes including hyperactivity, emotional symptoms, problems with peers and fewer prosocial behaviors. Children’s behavioral outcomes (‘current sample’, n = 89) were also compared with pre-COVID-19 data taken from the Growing Up in Ireland Study (‘GUI sample’, n = 327). The current sample exhibited significantly more behavioral difficulties than the pre-COVID GUI sample (p < 0.001). For the current sample, scores on each of the five SDQ subscales were significantly associated with a total impact score, and parents reported dissatisfaction with support services provided and willingness to engage in behavioral telehealth. Commitment is required to identify barriers to services faced by families in Ireland and to address the need for adapted behavior support services during periods of emergency.