Families can spend years waiting for a developmental assessment. We sought to understand supports caregivers had accessed by the time of their child's first multi‐disciplinary developmental assessment, the supports caregivers wanted, and the barriers caregivers reported to accessing these supports. We also sought to understand how government funding schemes (the National Disability Insurance Scheme) and sociodemographic factors influenced access to supports. Caregivers were emailed questionnaires on sociodemographic background and intervention history prior to their child's developmental assessment at a tertiary diagnostic and assessment service. Results from 202 caregivers showed most children were receiving less than 2 hours of support each week at assessment. The most common accessed supports were from general practitioners and pediatricians. Caregivers reported behavioral therapists (41%) and psychologists (29%) as the most desired but inaccessible child supports. Half of caregivers nominated a need for parenting interventions. The most frequent barriers to accessing child supports were wait lists, finance, and knowledge. Government funding improved access to the total number of services received (from 2.7 to 5.2 different services), but for disability specific services only (e.g., speech and occupational therapy). Results highlighted disparities for families without government funding, impacting certain groups (e.g., children over 7 years) and services (e.g., mental health). Socioeconomic disadvantage, parental separation, and, surprisingly, being from a non‐culturally/linguistically diverse background were associated with fewer services and more barriers. Results highlight the need to facilitate access to supports for families to align with existing recommendations.