"People need support from society not being kicked when they are down. They are being killed by the cold and indifference, and are running out of places to turn to as austerity hits services they use," Street Kitchen, an advocacy group, said in a statement.
In London, protesters will gather at Whitehall at 18:00 GMT to show solidarity with the homeless. "We will come together to say enough is enough," the group said.
The protest campaign, called the March For The Homeless 2015, was originally founded in Dublin, Ireland, where a protest and a candlelight vigil are planned for Wednesday. The event has been "liked" on Facebook by almost 10,000 people.
"Time to say goodbye at our Candelight Vigil to remember those that lost their lives from homelessness. Please bring a candle with you," the Dublin group said on Facebook.
Activists in the Irish capital will gather at 14:00 GMT at the Central Bank, from where they will march to Leinster House, the seat of the Irish parliament.
The Irish event will feature speakers from various charities supporting the homeless, and a sleepout that will allow people to experience urban "rough" accommodation while incongruously accompanied by a professional violinist playing classical music.
Canadians will rally in Montreal, Saskatoon, and Halifax to support their 200,000 compatriots who are estimated to experience homelessness every year.
In the United States, marches for the homeless will be held in the cities of Boston, Trenton, Honolulu, Ocala, Merced and Jacksonville. According to the US campaign's figures, an estimated 2 million Americans spend time homeless in the country every year.
