STV2 will be a rebranded version of STV's Glasgow and Edinburgh stations, and will include new licences for Aberdeen, Ayr and Dundee.
From 24 April, it will broadcast around the clock on Freeview as well as Sky and Virgin channels. It will also be streamed online via the STV Player.
STV said the channel would reach about 85% of viewers in its transmission area.
The launch will also mark the start of STV's new flagship news programme, STV News Tonight. Presented by Halla Mohieddeen, it will air weeknights at 19:00.
STV said the channel would also feature new programming including soap, drama and movies.
Bobby Hain, director of channels at STV, said: "STV2 is the first commercial TV channel with a distinct schedule for Scotland and we're excited to confirm the channel will launch on Monday 24 April.
"STV2 has Scotland at its core with an entertaining mix of local, Scottish and international content.
"Our flagship news programme, STV News Tonight, will air every weeknight as part of a diverse schedule including a daily live magazine show, programming showcasing key cultural events and local sport plus top quality drama and entertainment."
STV has confirmed the launch of a new commercial TV channel later this month.