Lðu or Luu without diacritics is a Vietnamese surname, and transliteration of the Chinese surname Liu (). Notable people with the surname include:
- (chữ Hán: ), one of "four important people" under ÃÂinh Dynasty of Emperor ÃÂinh Bá» Lénh. Lðu Cá was the first mayor of ÃÂại La city (modern Hanoi) nominated directly by ÃÂinh Tiên Hoàng after Vietnam regained independence from China.
- Lðu Quang VÃ
©, Vietnamese playwright, poet and writer
- ÃÂinh Xuân Lðu, Vietnamese ambassador to Poland and Israel
- Janette Luu, Vietnamese-American broadcaster
- Lðu Hữu Phðá»Âc, Vietnamese composer
- Lðu Huỳnh, Vietnamese American film director
- Lðu Huy Chao (born 1936), North Vietnamese military pilot
- Luu Meng, Chinese Cambodian chef, culinary author and hospitality entrepreneur
- Lðu Trá»Âng Lð, Vietnamese poet, writer, play writer
- Thang Luu, Vietnamese American professional poker
- Jane Luu (born 1963), Vietnamese American astronomer