In London, protesters will gather at Whitehall at 18:00 GMT. "We encourage people to stand in solidarity with our streets as well bring along items that may be of use to those who find themselves homeless," Street Kitchen, an advocacy group, said in a statement.
The protest march was originally founded in Dublin, Ireland, where a protest and a candlelit 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 in a Facebook posting.
Activists in the Irish capital will rally at 14:00 GMT at the Central Bank outside the Irish legislature, Dail Eireann. The event will also feature speakers from various charities supporting the homeless, and a sleepout allowing people to experience urban "rough" accommodation while incongruously accompanied by a professional violinist playing the music of Andrea Bocelli.