The Copyright Office rejected his application in 2022, finding that creative works must have human authors to be eligible to receive a copyright.
U.S. President Donald Trump's administration had urged the Supreme Court not to hear Thaler's appeal.
The Copyright Office has separately rejected bids by artists for copyrights on images generated by the AI system Midjourney. Those artists argued that they were entitled to copyrights for images they created with AI assistance - unlike Thaler, who said his system created "A Recent Entrance to Paradise" independently.