Mrs Cox would have been 42, and commemorations are being planned to celebrate her “warmth, love, energy, passion and flair”.
The MP shares the same birthday with Bernard Kenny, the pensioner who was injured when he stepped in to try to help her as she was shot and stabbed to death, who will be 78.
Events are being held in Mrs Cox’s constituency of Batley and Spen while a main commemoration will take place in London’s Trafalgar Square, which will be preceded by a floating commemoration on the River Thames.
People are also expected to gather and mark her birthday in Brussels, New York, Washington and Nairobi.
The event in Batley will be in the Market Place at 4pm. The programme will include musical tributes as well as contributions from friends and colleagues “who share Jo’s belief in the goodness of humanity”, said Dan Howard, a member of Mrs Cox’s office staff.
Her family and friends said in a statement: “Our gift to her, her family and all those who loved and cherished her, will be to come together to show the world there is more that unites us than divides us.
“The coming together of thousands of people in love and solidarity with Jo proves the strength of her ideas and values.
“Supporters will come together to celebrate what Jo’s warmth, love, energy, passion, flair, Yorkshire heritage and belief in the humanity of every person in every place, from Batley and Spen to Aleppo and Daraya.”
The events, they said, will be “both a celebration of Jo’s life and a collective calling to action to give a voice to the voiceless and to treat everyone with respect and dignity, especially those we disagree with”.
A fundraising page set up to support some of the charities close to her heart has reached around £700,000.