Niilo is a male given name. People named Niilo include:
Niilo Halonen (1940–2025), Finnish ski jumper Niilo Jääskinen (born 1958), Finnish lawyer and politician Niilo Mäenpää (born 1998), Finnish footballer Niilo Paasivirta, Finnish internet personality Niilo Saarikivi (born 2003), Finnish footballer Niilo Sevänen (born 1979), Finnish death metal musician Niilo Tammisalo, Finnish influential sports figure Niilo Wälläri (1897–1967), Finnish Socialist, syndicalist leader Niilo Yli-Vainio (1920–1981), Finnish Pentecostal leader
As a surname Tiit Niilo (born 1962), Estonian politician
See also 2972 Niilo (1939 TB), a Main-belt Asteroid discovered in 1939