Zionist as a pejorative or Zio (/ˈzaɪoʊ/ ZY-oh) is a term, commonly used by anti-Zionists described by academics, politicians and Jewish organizations as antisemitic, including the American Jewish Committee and the British Labour Party.

The use of the compounded "Zio" as a slur is first recorded by the 1990 edition of the American Jewish Yearbook as in the term "Zionazi", spraypainted as graffiti on the campus of SUNY-Binghamton. The website WikiZio, run by former grand wizard of the Ku Klux Klan (KKK) David Duke uses "Zio" as a noun or as a hyphenated or unhyphenated adjective. Other variations of "Zio-" include "Zio-Communism", "Zio-economics", "Zio-supremacism", and "Zio-occupied America".

Ben Samuels, writing for Haaretz, has claimed that the term was popularized first by David Duke and then later by leftists and members of the British Labour Party. In 2016, the British Labour Party released an inquiry into antisemitism stating that "Epithets such as [...] 'Zio' and others should have no place in Labour party discourse going forward." Speaking at the inquiry's launch, party leader Jeremy Corbyn stated that "'Zio' is a vile epithet that follows in a long line of earlier such terms that have no place whatsoever in our party."

In 2017, the organizers of the Chicago Dyke March faced accusations of antisemitism after their Twitter account used the term "Zio tears". In April of the same year, Terry Couchman, an election candidate of the British Labour Party, was suspended over his use of "ZioNazi" in a post criticising Israel. Tony Greenstein, another then-member of the British Labour Party, was accused of antisemitism and expelled from the party in 2018 for using the term "Zios" among other allegations.

According to the American Jewish Committee (AJC), "Zio" is used by antisemites to pass off their antisemitism as "anti-Zionism", pointing out that "Zio" is an euphemism for "Jew". This view was shared by prominent Jewish civil rights advocacy Anti-Defamation League. Similarly, progressive journals like the Mosaic Magazine referred to "Zio" as a "new anti-Jewish slur". Writer Ariel Sobel of the Jewish Journal also pointed out that "Zio" was an antisemitic slur with roots within antisemitic right-wing extremist circles that had been adopted by some progressives in their activism. Well-known Czech-Israeli Jewish Holocaust historian Yehuda Bauer succinctly called the "Zio-Nazi" slur hate speech.

During the Israel-Hamas war, the term "Zionist" became a popular pejorative among the political left, leading to the Meta's imposition of restrictions on the use of the term, while surveys found that 80% British Jews identified as "Zionist" and 85% American Jews believed in the importance of the U.S. to support Israel respectively.

• Anti-Zionism
• New antisemitism