Arthur Simpson-Kent is wanted in connection with the murder of Sian Blake, a former actress in the popular soap opera EastEnders, and the two boys, Zachary and Amon. The family had been reported missing in mid-December.
"The suspect has been arrested by police and I can confirm his identity," a police spokesman said. "He was at a hideout in Western Region. With the kind of collaboration between the police and public that we have, we managed to nab him there."
A spokesman for Interpol in Ghana said the suspect was being driven back from the port city of Takoradi to the capital Accra and would arrive late on Saturday.
In a statement released in London, Scotland Yard police said they had been "made aware of an arrest in Ghana" and were working alongside Ghanaian authorities.