is a Finland-Swedish surname that may refer to
Benedict Zilliacus (1921–2013), Finnish journalist, author, scriptwriter and translator Bruno Zilliacus (1877–1926), Finnish athlete Jutta Zilliacus (1925–2026), Finnish-Estonian journalist, author and politician Konni Zilliacus (senior) (1855–1924), Finnish politician, author and independence activist Konni Zilliacus (1894–1967), Finnish-born British politician Linda Zilliacus (née Gyllenberg, born 1977), Finnish actress Thomas Zilliacus (born 1956), Finnish businessman Tobias Zilliacus (born 1971), Finnish actor