Lady Di is a diminutive of Lady Diana Spencer, later Princess of Wales (1961–1997).
Lady Di may also refer to:
- People
- Fictional characters
- Music
- Other
- Lady Di, a 1953 NZR DSA class locomotive, withdrawn in 1984
- The "Lady Di", a pink variant of the tricorne hat
- The "Lady Di", 1980s pageboy women's hairstyle