William Birch, Bill Birch or Billy Birch may refer to:

• Bill Birch (born 1934), New Zealand politician
• Bill Birch (footballer) (born 1944), English and Australian footballer and coach
• Billy Birch (1831–1897), American minstrel performer
• William Birch (Australian cricketer) (1849–1897), Australian cricketer
• William Birch (English cricketer) (1863–1940), English cricketer
• William Birch (footballer) (1887–1968), English footballer
• William Birch (painter) (1755–1834), English and US miniature painter, enameler and engraver
• William Birch (settler) (1842–1920), English settler in North Island, New Zealand
• William Fred Birch (1870–1946), American politician
• William John Birch (1811–1891), English freethinker