The New Blue Party of Ontario (abbreviation: New Blue; French: Nouveau Parti Bleu de l'Ontario) is an anti-establishment centre-right political party in the Canadian province of Ontario. Founded in 2020, the party is led by Jim Karahalios, the husband of Belinda Karahalios, the party's first Member of Provincial Parliament.

In late 2017, Jim Karahalios, a corporate lawyer with a bachelor and master degree in civil engineering, was sued by the Progressive Conservative Party of Ontario in retaliation for Karahalios's founding the activist groups "Axe The Carbon Tax" (opposing the party's pro-carbon tax position) and "Take Back Our PC Party" (challenging the party's acceptance of nominations that resulted in allegations of electoral fraud). Karahalios won the lawsuit when Superior Court Justice Paul Perell wrote a scathing decision against the party ruling the lawsuit was a "strategic lawsuit against public participation” intended to stifle dissent.

On March 1, 2018, Karahalios received an apology from interim leader of the PC Party, Vic Fedeli. The Toronto Star described Karahalios with the following: 

Karahalios was instrumental in exposing problems at Tory candidate nomination elections, the policy-making process and other abuses of the party constitution...Karahalios, a Cambridge corporate lawyer, has emerged as a conscience of the PC party. His crusade against Brown’s embrace of a carbon tax has been embraced by all the leadership hopefuls in the March 10 PC leadership contest.

Nine days later, on March 10, 2018, Doug Ford was elected as leader of the Progressive Conservative Party of Ontario. His leadership campaign platform, and those of the other three candidates in the race, embraced the themes of Karahalios's "Axe the Carbon Tax" and "Take Back Our PC Party" campaigns as described here in the Toronto Sun, here in the Toronto Star, and here in the Waterloo Record.

Following Ford's election as Ontario PC Party leader, Belinda Karahalios ran for the party's nomination in the riding of Cambridge. She won the nomination in just over two weeks and in the 2018 Ontario election she was elected MPP for the riding as the Progressive Conservative candidate.

In November 2018, Jim Karahalios ran for the presidency of the Ontario Progressive Conservative Party and later filed a lawsuit against the party after his defeat, alleging the election process was manipulated, election rules were breached and that ballot boxes were allegedly stuffed in order to elect his competitor, Brian Patterson, who was endorsed by Doug Ford.

In 2019, Belinda Karahalios introduced her first private member's bill - Bill 150, Ensuring Transparency and Integrity in Political Party Elections Act, 2019. Ford initially indicated his government would oppose the bill but by second reading the bill passed with the unanimous support of all MPPs in attendance at Queen's Park. The Ford PC government never allowed the bill to return from committee to third reading and eventually killed the bill when they reset the legislative sitting in September of 2021.

In January of 2020, Jim Karahalios announced he was running in the 2020 Conservative Party of Canada leadership election. By March 19, 2020, Karahalios was the third candidate in the race to raise the $300,000 in donations and 3,000 endorsement signatures the party required to have his name added to the ballot. On March 20, 2020, the party disqualified Karahalios from the race. On May 20, 2020, Superior Court Justice Paul Perell ruled Karahalios could re-enter the race but before Karahalios could pay the additional $100,000 fine imposed on him by the party's leadership committee, the party disqualified Karahalios from the race a second time.

Two months later, on July 21, 2020, Belinda Karahalios was expelled from the Progressive Conservative caucus by Doug Ford after voting against Bill 195, the Reopening Ontario (A Flexible Response to COVID-19) Act, which would expand the government's emergency authority during the COVID-19 pandemic. Karahalios voted against the legislation, calling it an "unnecessary overreach on our parliamentary democracy." 

A month later, Belinda Karahalios, her husband Jim, and 17 other members of the Ontario PC Party were unlawfully removed from the Cambridge PC Riding Association Board as a result of the party executive, led by Brian Patterson, voting to "de-register" the riding association with Elections Ontario against the party’s own constitutional rules.

On October 12, 2020, Jim and Belinda Karahalios released a video announcing that they were forming a new political party, claiming that the Ontario PC Party was beyond redemption. Stating that there "is no party in the Ontario legislature defending the taxpayer, defending small business, defending places of worship, promoting freedom, promoting democracy or fighting political corruption."

On January 7, 2021, the New Blue Party was officially registered by Elections Ontario. Party leader Jim Karahalios stated that the party would focus on supporting the taxpayer, places of worship and small business.