Russian driver Daniil Kvyat will stay at Toro Rosso next season in an unchanged lineup with Spaniard Carlos Sainz.
In a statement headed "Hands off, they're ours", the Red Bull feeder team ended media speculation about Kvyat's future and the possibility of him moving elsewhere.
Sainz, who was confirmed in June, had also been linked to a possible vacancy at the works Renault team.
"To those other teams who have been sniffing around our talented pair, well hands off, they're staying put," Toro Rosso declared ahead of the US Grand Prix.
Kvyat, who was demoted from the main Red Bull Racing team in May to make way for teenage Dutch sensation Max Verstappen, thanked his employers for having faith in him.
"I'm very happy to stay with a team that feels like home to me. I'm really looking forward to continuing the hard work together in 2017 and I'm really aiming high," he said.
Team principal Franz Tost said it made sense to retain a stable lineup for a year that will see a major technical shake-up, with faster cars and wider tyres, as well as the team's switch from Ferrari to Renault power units.
The announcement leaves Force India and Renault in the spotlight as the main teams with seats to fill.
Williams also have an announcement to make with Canadian teenager Lance Stroll expected to replace retiring Brazilian Felipe Massa.
Force India have Mexican Sergio Perez confirmed with his current German team mate Nico Hulkenberg switching to Renault. The second seats at both teams are yet to be confirmed.
