Pyopneumothorax with bronchopleural fistula is a rare complication of lung infection. We herein report a case of pyopneumothorax with bronchopleural fistula caused by Porphyromonas gingivalis infection, a common pathogenic pathogen of periodontitis, in a 49‐year‐old man with periodontitis. The patient was admitted with respiratory failure. Pleural puncture yielded a lot of gas continually and foul‐smelling light brown pus, which was found to be caused due to infection with P. gingivalis by the metagenomic next generation sequencing (mNGS) and anaerobic culture. [ABSTRACT FROM AUTHOR]