Theresa May and other party leaders will stop campaigning for an hour to remember the Labour MP, who used her maiden speech in the Commons to say: "We are far more united and have far more in common than that which divides us."
Her widower Brendan Cox said the move would "send a powerful message" of unity, coming ahead of the first anniversary of the mother-of-two's murder in June.
He said: "Doing so in such a coordinated way will, we hope, send a powerful message that whatever our political disagreements, we really do hold more in common and show a united front against hatred and extremism in all its forms.
"Elections are huge moments of national importance and deserve to be taken seriously. But we also need to get a better balance.
"We spend way too much time fixated on the areas we disagree with each other and need to create more moments where we come together as a country.
"That's what I'm focused on and after polling day, I am sure that's exactly what people all over the UK will be crying out for."
Labour leader Jeremy Corbyn is due to visit an arts centre in Liverpool, while Liberal Democrat Tim Farron will attend a community picnic in Kendal in his constituency and Green leader Caroline Lucas will be at a church project in Brighton.
In Mrs Cox's former constituency of Batley and Spen, in West Yorkshire, the Conservative, Labour, Liberal Democrat and Green candidates will come together at farmers event raising money for a special care baby unit.
The mother-of-two, 41, was shot and stabbed multiple times by right-wing extremist Thomas Mair in her constituency last June. He was later handed a whole-life prison sentence for her murder.
To mark the anniversary of her death, Mr Cox has organised the Great Get Together from June 16 to 18, where thousands of gatherings such as street parties, picnics and coffee mornings will be held across the country.
In an interview with the Sun on Sunday's Fabulous Magazine, the sister of Mrs Cox, Kim Leadbeater, revealed she often feels guilty when spending time with her niece and nephew.
The 41-year-old said there are times that she is with Cuillin, six and Lejla, four, which are "really difficult".
"Sometimes I will be just reading them a book and I'll feel suddenly guilty, thinking to myself that Jo should be doing this with them, not me," she said.
"But I know that she would want me to be there for all of those milestones, so I am and always will be. Jo was clear that aunties should spoil the kids, so I do that all the time."
Ms Leadbeater said in the weeks and months after the murder of her sister, she did not know how she coped, and revealed she has never thought about her sibling's killer.
"The one thing in this whole sad situation that I have control of is how I feel and how I react. My choice right now is to not be beaten by him," she added.