Computer science enrollment declined during the 2025-26 academic year for the first time in roughly two decades, according to new research by Jacob Light, an economist at Stanford University's Hoover Institution. Separate National Student Clearinghouse Research Center data showed undergraduate enrollment in Computer and Information Sciences and Support Services at four-year colleges fell 8.1% year over year in the fall of 2025. Using a dataset covering more than 50 million course sections offered since 1996 across 1,019 US colleges and universities, Light tracked long-term enrollment patterns alongside the growing capabilities of large language models. Light told Business Insider that, at the average school in his sample, enrollment in computer science classes fell about 4.6% year over year, while computer science's share of overall course enrollment dropped 6.3 percentage points. "In 2025-26, Computer Science enrollment share declined for the first time in roughly two decades, interrupting a period of sustained and unusually rapid growth," Light wrote. The timing overlaps with the rapid adoption of generative AI, but Light cautioned that the data does not show artificial intelligence caused the decline, treating the enrollment patterns as descriptive evidence rather than an estimate of the causal effect of ChatGPT or AI exposure on student demand.