Purpose <p>Research has indicated an increase of adults being referred for first-time autism assessment though there are limited tools designed to assess autism in adulthood. Concerns have arisen regarding higher rates of camouflaging in adulthood-diagnosed adults and how this may restrict clinicians’ ability to observe all autistic traits during assessments with an unfamiliar person. The Brief Observation of Symptoms of Autism (BOSA), derived from the Autism Diagnostic Observation Schedule-2 (ADOS-2), was developed during the COVID-19 pandemic. The BOSA focuses on a 12- to 14-minute interaction with a familiar other and has shown promise as an adapted tool. Due to the short duration and limited materials, the BOSA may be useful as a supplemental measure for first-time diagnosis of adolescents or adults, or as a brief method to characterize research participants.</p> Methods <p>The study sought to explore the utility of the BOSA and its correspondence to the ADOS-2 with a sample of forty-two adolescents and adults who completed the ADOS-2 and BOSA within the same visit at an autism lab within a university in New Jersey.</p> Results <p>Sensitivity and specificity of the ADOS-2 Modules 3 and 4 and BOSA F2 were comparable. The instruments yielded highly similar classifications and item scores. Differences in some item scores highlight limitations of very brief observations and suggest potential areas for refinement of the BOSA.</p> Conclusion <p>The BOSA may provide an additional context in which to consider diagnostic features when assessing adolescents and adults and offers a feasible option for sample characterization in research.</p>