Katja is a feminine given name. In Germany, the Netherlands, Flanders, Scandinavia and Slavic-speaking countries, it is a pet form of Katherine. Katja may refer to:
In music:
Katja Andy (1906–2013), German-American pianist
Katja Ebstein (born 1945), German singer
Katja Glieson, Australian recording artist
Katja Schuurman (born 1975), Dutch actress, singer and television personality
In modelling:
Katja Shchekina (born 1986), Russian supermodel
In sports:
Katja Demut (born 1983), German triple jumper
Katja Dieckow (born 1984), German diver
Katja Ebbinghaus (born 1948), German tennis player
Katja Gerber (born 1975), German judoka
Katja Haller (born 1981), Italian professional biathlete
Katja Keller (born 1980), German heptathlete
Katja Koren (born 1975), former Slovenian alpine skier
Katja Kraus (born 1970), German former footballer
Katja Langkeit (born 1983), German team handball player
Katja Lehto, Finnish female ice hockey player
Katja Nass (born 1968), German fencer
Katja Nyberg (born 1979), (naturalized) Norwegian team handball player
Katja Požun (born 1993), Slovenian ski jumper
Katja Rajaniemi, Finnish ski-orienteering competitor
Katja Riipi, Finnish female ice hockey player
Katja Roose (born 1981), Dutch female professional kite surfer
Katja Schroffenegger, Italian football goalkeeper
Katja Schülke (born 1984), German team handball player
Katja Seizinger (born 1972), German alpine skier
Katja Tengel (born 1981), German sprinter
Katja Trödthandl, Austrian football midfielder
Katja Višnar (born 1984), Slovenian cross-country skier
Katja Ziliox (born 1970), retired German swimmer
In other fields:
Katja Boh (1929–2008), Slovenian sociologist, diplomat, politician
Katja Flint (born 1959), German actress
Katja Herbers (born 1986), Dutch actress
Katja von Garnier (born 1966), German film director
Katja Kassin (born 1979), German pornographic actress
Katja Kipping (born 1978), German politician, chairwoman of the Left Party
Katja Lange-Müller (born 1951), German writer
Katja Medbøe (1945–1996), Norwegian actress
Katja Mragowska (born 1975), Polish-German artist
Katja Pettersson, Finnish designer
Katja Rahlwes (born 1967), German fashion photographer
Katja Riemann (born 1963), German actress
Katja Schuurman (born 1975), Dutch television personality
Katja Špur (1908–1991), Slovene journalist, writer, poet, translator
Katja Suding (born 1975), German politician
Katja Thater (born 1966), German poker player
Katja Tukiainen (born 1969), Finnish artist
Katja Woywood (born 1971), German actress, former child star
Katja Zoch, voice actress, plays Zelda in The Swan Princess
Fictional:
Katja Brandner, fictional character on German soap opera Verbotene Liebe
Katja Phillips, attorney at fictional firm Morgan Siler in Kermit Roosevelt III's 2005 legal thriller "In The Shadow Of The Law".
Katja Obinger, German clone on the television series "Orphan Black"