Julije Knifer (23 April 1924, Osijek – 7 December 2004, Paris) was a Croatian abstract painter and a founding member of the 1960s art collective Gorgona.
Knifer studied painting at the Akademija likovnih umjetnosti u Zagrebu, Zagreb (1950–1956).
The central motif of Knifer’s art is the exploration of meander, a geometric form which he had been creating since 1960 in various painting techniques such as print, oil, acrylic paint, collage and mural. An example of which is the colossal meander created by Knifer on a 20 x 30 m canvas in a quarry in Tübingen (1975).
He exhibited at many national and international shows including the New Tendencies exhibitions (1961, 1963, 1969 and 1973), Art Abstrait Constructif International at the Denise René Gallery (Paris, 1961–1962), Konstruktivisten at the Städtisches Museum Leverkusen (Leverkusen, 1962), Oltre l’informale (San Marino, 1963), the Venice Biennale (1976 and 2001), the São Paulo Art Biennale (1973 with Juraj Dobrović and Vjenceslav Richter, 1979 and 1981). He collaborated with the Dany Keller Gallery in Munich, the Hoffmann Gallery in Friedberg and the Frank Elbaz Gallery in Paris.
In 1994 he moved to Paris, where he lived until his death. His first posthumous exhibition was organized by Arnauld Pierre at the Frank Elbaz Gallery in Paris (2010). In 2002 he was the recipient of the Vladimir Nazor Life Achievement Award.
- Julije Knifer, Zagreb: Galerija suvremene umjetnosti, 1966. (Croatian)
- Julije Knifer, Zagreb: Galerija suvremene umjetnosti, 1970. (Croatian)
- Crtezi, 1959-1979, Zagreb: Galerija suvremene umjetnosti, 1980. (Croatian)
- Juraj Dobrović, Julije Knifer, Vjenceslav Richter. Yugoslavia. XII Bienial de Sao Paulo, ed. Božo Bek, Interrepublic Coordinative Commitee for Cultural Relations with Foreign Countries of R.S.F. Yugoslavia, 1973,  pp. (English)
- Julije Knifer, ed. Predrag D. Grubić, Rovinj: Galerija Adris, 2013, 56 pp. (Croatian)
- Žarko Radaković (ed.), Julije Knifer. Mäander 1960-1990, Stuttgart: Flugasche, 1990. (German)
- Žarko Radaković, Knifer, Povest o Juliju Kniferu, Belgrade: Radio B92, 1994.
- Arnauld Pierre, Julije Knifer – Méandres, Paris: Adam Biro, 2001, 128 pp. (French)
- Zvonko Maković, Julije Knifer, Zagreb: Meandar & Studio Rašić, 2002, 272 pp.  (Croatian)