The kosher tax conspiracy theory states that the kosher certification of products (typically food) is an extra tax collected from unwitting consumers for the benefit of Jewish organizations. It is mainly spread by Antisemitic, white supremacist, and other extremist organizations, and is considered a canard or urban legend. Similar claims are made that this "Kosher tax" (or "Jewish tax") is "extorted" from food companies wishing to avoid a boycott, and used to support Zionist causes or the state of Israel.
University of Pittsburgh professor of sociology Kathleen M. Blee reported that some racist groups encourage consumers to avoid this "Jewish tax" by boycotting kosher products.
The 2000 Annual Audit of Antisemitic Incidents by the B'nai Brith Canada reported citizens being encouraged to request a refund from the government on their income taxes.
In 1997 the Canada Revenue Agency issued a news release noting the existence of flyers recommending that consumers claim a deduction on their taxes "because they supposedly contributed to a Jewish religious organization when they purchased these groceries." In it Jane Stewart, then Minister of National Revenue stated, "The intent and message in this literature is deeply offensive to the Jewish community and, indeed, to all Canadians. The so-called 'deduction' described in these flyers does not exist and I urge all taxpayers to ignore this misleading advice".
During the 2014 Quebec provincial election campaign, Parti Québécois candidate and academic
Louise Mailloux defended the PQ government's proposed Quebec Charter of Values by asserting that kosher and halal certification was a religious tax used to fund religious wars and enrich religious leaders. The Centre for Israel and Jewish Affairs called on the PQ to debunk the “urban legend of the kosher tax” but PQ leader and Premier of Quebec Pauline Marois defended her candidate's comments saying of Mailloux, "Her writings are eloquent, I respect her point of view.”