Maciej (Polish pronunciation: [ˈmat͡ɕɛj]) is a Polish given name, the etymological equivalent of Matthias. Its diminutive forms are Maciek, Maciuś.
Namedays according to Polish calendar: 30 January, 24 February, 14 May[citation needed]
Maciej may refer to:
- Maciej Cieślak (born 1969), Polish guitarist and songwriter
- Maciej Dunal (1953–2014), Polish actor and singer
- Maciej Fortuna (born 1982), Polish jazz trumpeter, composer and musical educator
- Maciej Golubiewski (born 1976), Consul General at the Consulate General of the Republic of Poland in New York City
- Maciej Jachowski (born 1977), Polish actor
- Maciej Kozłowski (1957–2010), Polish actor
- Maciej Łukaszczyk (1934–2014), Polish pianist
- Maciej Maleńczuk (born 1961), Polish singer, guitarist and poet
- Maciej Małecki (born 1940), Polish composer and pianist
- Maciej Musiał (born 1995), Polish actor
- Maciej Silski (born 1976), Polish singer
- Maciej Stuhr (born 1975), Polish actor, comedian and impressionist
- Maciej Ślesicki (born 1966), Polish director and screenwriter, co-founder of the Warsaw Film School.
- Maciej Wojtyszko (born 1946), Polish film director, screenwriter and fiction author
- Maciej Zembaty (1944–2011), Polish artist, writer, journalist, singer, poet and comedian
- Maciej Bębenek (born 1984), Polish footballer
- Maciej Bielecki (born 1987), Polish cyclist
- Maciej Bodnar (born 1985), Polish road racing cyclist
- Maciej Bydliński (born 1988), Polish alpine skier
- Maciej Dąbrowski (born 1987), Polish footballer
- Maciej Gajos (born 1991), Polish footballer
- Maciej Gębala (born 1994), Polish handball player
- Maciej Górski (born 1990), Polish footballer
- Maciej Hreniak (born 1989), Polish swimmer
- Maciej Iwański (born 1981), Polish footballer
- Maciej Janowski (born 1991), Polish speedway rider
- Maciej Jewtuszko (born 1981), Polish mixed martial artist
- Maciej Korzym (born 1988), Polish footballer
- Maciej Kot (born 1991), Polish ski jumper
- Maciej Lampe (born 1985), Polish basketball player
- Maciej Pałyszko (born 1978), Polish hammer thrower
- Maciej Piaszczyński (born 1989), Polish speedway rider
- Maciej Pospieszyński, Polish glider aerobatic pilot
- Maciej Rybus (born 1989), Polish footballer
- Maciej Skorża (born 1972), Polish football manager
- Maciej Śliwa (born 2001), Polish footballer
- Maciej Staręga (born 1990), Polish cross-country skier
- Maciej Szczęsny (born 1965), Polish footballer
- Maciej Urbańczyk (born 1995), Polish footballer
- Maciej Zieba (born 1987), Polish-German footballer
- Maciej Żurawski (born 1976), Polish footballer
- Maciej Kowalczyk (born 2002), Polish-American hockey player and expert computer scientist
- Maciej Cegłowski, Polish-American web developer and writer, owner of the bookmarking service Pinboard
- Maciej Aleksy Dawidowski (1920–1943), Polish anti-Nazi resistance fighter
- Maciej Dziewoński (died 1794), Polish priest and Russian spy
- Maciej Franz (born 1969), Polish historian
- Maciej Kranz (born 1964), Polish-American Silicon Valley executive
- Maciej Kuroń (1960–2008), Polish chef, culinary publicist and journalist
- Maciej Łubieński (1572–1652), primate of Poland and archbishop of Gniezno
- Maciej Miechowita (1457–1523), Polish renaissance scholar, professor of Jagiellonian University, historian, chronicler, geographer, and medical doctor
- Maciej Rybiński (1945–2009), Polish journalist, publicist, satirist and writer
- Maciej Kazimierz Sarbiewski (1595–1640), Europe's most prominent Latin poet of the 17th century
- Maciej Stachowiak (born 1976), Polish-American software developer and notable proponent for open source software and web standards, and a leader of the WebKit development team.
- Maciej Stoiński (born 1972) Polish businessman and CEO of the Piotr i Paweł supermarket chain.
- Maciej Stryjkowski (ca. 1547–1593), Polish historian
- Maciej Sulkiewicz (1865–1920), lieutenant general of the Russian Empire, Prime Minister of Crimea, and Chief of General Staff of Azerbaijani Armed Forces
- Maciej Zamoyski, Polish nobleman
- Maciej Zaremba (born 1951), Swedish journalist and author
- Maciej Zień (born 1979), Polish fashion designer
- Maciej Żurowski (1915–2003), Polish historian of French literature and translator