<p>Children of migrants have been reported to have increased likelihood of various neurodevelopmental disorders (NDDs), but little is known about differences in referral patterns for diagnostic assessment. This retrospective cohort study aimed to examine differences in referral rates and subsequent diagnostic outcomes between children with native (Icelandic parents) and migrant (at least one parent foreign-born) backgrounds in Iceland in five referral-year cohorts (2014–2018) using a nationwide database. Among 1,367 new referrals, children with migrant backgrounds (31.6%) were consistently referred at a significantly higher rate for assessment due to suspected autism spectrum disorder (ASD), intellectual disability (ID), or motor disorders such as cerebral palsy (CP), particularly children who were under 6 years old, male and second-generation immigrants (born in Iceland to two foreign-born parents). At follow-up, diagnostic outcomes most consistently differed for speech and language disorders (SLD), with significantly higher rates among children with migrant backgrounds across all cohorts. They also had significantly elevated rates of ASD diagnosis in three of the five cohorts, but no difference was found when co-occurring ID and SLD were excluded. Rates of ID (significantly elevated in one cohort) and CP (no difference in any cohort) were similar to those of children with native backgrounds. While it is positive that children with NDDs are not being overlooked due to their migrant backgrounds, the elevated rates of suspected NDDs in this population suggests a need for improved primary-level support with the aim of enhancing their well-being while reducing the demand for specialized diagnostic assessment and long-term support.</p>