Ricciardo won the 2009 British Formula 3 championship
Daniel Ricciardo will be Toro Rosso's third and reserve driver for 2011.
The 21-year-old Australian is a product of the Red Bull Young Driver Programme and was fastest in the younger driver tests in Abu Dhabi last week.
He will replace regular drivers Jaime Alguersuari and Sebastien Buemi on an alternating basis in the Friday morning practice sessions.
"My ultimate aim is to be a Formula 1 driver," Ricciardo said. "This is the best step towards achieving that."
Ricciardo, who is expected to put pressure on Buemi in the team, added: "I am really excited at the prospect of driving for Scuderia Toro Rosso in the free practice sessions next year, so I have to say thanks to Red Bull for this great opportunity."
While Toro Rosso have decided to keep their driver line-up of Alguersuari and Buemi for 2011, team principal Franz Tost has said that Ricciardo has a lot to offer.
"When our team was created, its stated aim was to bring on young drivers from the Red Bull Junior Programme, so Daniel's appointment as our third driver is an obvious one," Tost stated.
"Although Daniel has done some F1 testing already, running on Fridays at the grands prix will give him a valuable insight into the additional pressures of doing it for real during a race weekend.
"I am also sure that having a hungry youngster on the books will keep our current driver pairing nice and sharp."