William Lacy

William Lacy or Bill Lacy could refer to:


 * William Lacy (Catholic priest) (died 1582), English Catholic priest and martyr
 * William Henry Lacy (1858-1925), American Methodist missionary to China
 * William S. B. Lacy (1910-1978), American Diplomat
 * Bill N. Lacy (born 1933), American academic
 * William H. Lacy Jr. (1945-2016), American businessman
 * Bill Lacy (political operative), Director of the Robert J. Dole Institute of Politics