fNIRS 2026 is the biennial international meeting of the Society for Functional Near-Infrared Spectroscopy (SfNIRS), bringing together researchers and practitioners in optical brain imaging and neurophotonics. Scheduled for October 16–19, 2026 in Macau, China, the conference showcases cutting-edge developments in functional near-infrared spectroscopy (fNIRS), high-density diffuse optical tomography (HD-DOT) and related methodologies for studying brain function and behavior.