In February 2023, an 11-year-old girl in Cambodia developed severe respiratory symptoms and died of pneumonia and respiratory failure after testing positive for influenza A(H5). Contract tracing and testing identified her father as positive for influenza A(H5). Investigations revealed both were likely exposed to the same sick and dead poultry. Control measures included culling sick poultry and providing health education in the community on handling infected birds. Highly pathogenic avian influenza A(H5N1) viruses continue to pose public health risks in Cambodia.