Purpose <p>Standardized, high-fidelity screening is an effective strategy for early identification of autism. However, studies show that many families do not attend an evaluation following a positive screening result. This study aims to address a critical gap in understanding factors influencing autism evaluation attendance.</p> Methods <p>Children (<i>n</i> = 895) from two large-scale, primary care autism screening studies were invited to attend a diagnostic evaluation based on a screener result indicating higher likelihood for autism. We explored whether evaluation attendance differed based on sex, race, ethnicity, maternal education, or age at the time of screening. In addition, we explored whether screener scores differed between children who attended the evaluation versus those whose families declined.</p> Results <p>Evaluation attendance differed significantly between the two studies, but did not differ significantly within either study based on child’s sex, race, ethnicity, or maternal education. The age at which the child was screened was a significant predictor of evaluation attendance, with higher attendance when the first positive screen was at 18 months (57%) compared to 12 months (38%) or 15 months (30%). In addition, children who completed an evaluation had screening scores indicating more autism characteristics compared to children who did not attend an evaluation (all <i>t</i> &gt; 1.798, all <i>p</i> &lt; .038).</p> Conclusion <p>These findings emphasize the role of screening factors while de-emphasizing the role of child demographics on families’ attendance following a positive screening result.</p>