PY, Py or py may stand for:

• Pinyin, a system of romanization (phonetic notation and transliteration to roman script) for Mandarin Chinese used in the People's Republic of China.
• The Internet top-level domain for Paraguay, .py.
• The Python programming language's typical filename extension, .py.
• The Portsmouth yardstick, used as a rating system in yacht racing and dinghy racing.