Background <p>This study investigates the prevalence, nature, and impact of misinformation, stigma, and general information about autism spectrum disorder (ASD) on TikTok and Instagram.</p> Objective <p>The aim of this research was to analyze the content related to ASD on TikTok and Instagram to understand the nature of misinformation, stigma, and their influence on public perceptions of ASD.</p> Methods <p>A TypeScript-based scraper was used to extract posts from TikTok and Instagram, focusing on the hashtags #ASD, #Autism, and #ASDinfo. Data was collected over a five-year period from January 2018 to January 2024.</p> Results <p>The analysis found that misleading statistics (MIS3) were the most common form of misinformation, accounting for 52.5% of all misinformation. Instagram had a higher prevalence of misinformation (85%) compared to TikTok (74%). In terms of stigma, negative stereotypes (STIG1) were most prominent, with TikTok showing a higher frequency of stigma (88.5%) than Instagram (80%). Supportive community posts (INFO2) made up 48.5% of the posts, with Instagram again leading (65%) over TikTok (63.5%), although TikTok had more interactive engagement. Chi-square tests indicated statistical significance for derogatory language (<i>p</i> = 0.049) and personal stories (<i>p</i> = 0.038), both of which were more prevalent on TikTok. No significant differences were found in other categories.</p> Conclusions <p>This study highlights the distinct dynamics of misinformation and stigma across social media platforms, with TikTok showing greater negativity and interactive content, while Instagram provided more supportive community posts. The findings emphasize the need for targeted interventions to address the spread of misinformation and harmful stereotypes about ASD on these platforms.</p>