Both STV and UTV have agreed new networking arrangements with ITV, becoming an affiliate of the Channel 3 network as a result.
The new agreements have yet to be given regulatory approval by Ofcom.
The STV deal will see the commercial broadcaster pay a settlement balance of £10.8m to ITV over a period of 18 months, through both programming and cash.
Rob Woodward, CEO of STV said: "Today's announcement confirms the stability and certainty of long term, commercially sustainable networking arrangements between the Channel 3 licence holders. STV remains 100% committed to its public service broadcasting credentials, to delivering a distinct schedule for Scotland and to providing a platform for informed debate. We are delighted to have reached agreement on a set of terms which will benefit our viewers and consumers across all distribution platforms."
Adam Crozier, Chief Executive of ITV plc, added: "We look forward to continuing our positive relationship with STV under a new affiliate agreement. This agreement, which is still subject to regulatory approval, represents a major milestone for us as it consolidates and simplifies the ITV Network."
Meanwhile, the new Media Right Agreement will also see UTV granted access to all ITV 1 programming for use in Northern Ireland, while an Operational Agreement will include the distribution of UTV HD on Sky and Freesat in Northern Ireland, and on Virgin.
ITV will also continue to handle UTV’s advertising sales.
John McCann, Chief Executive of UTV, commented: "We are delighted to agree new terms with ITV plc for the future provision of programming, transmission and sales services to UTV as the Channel 3 licence holder in Northern Ireland.
"The proposed new agreements retain the strength offered by the original Channel 3 regional partnerships in the ITV Network but provide the flexibility required for public service broadcasters to operate more effectively in today's market on all platforms.
"UTV is totally committed to providing Northern Ireland with quality public service programming in the future as we have for more than 50 years," he added.
Michael Wilson, managing director of UTV Television said: "UTV is by far the most watched channel in Northern Ireland, delivering the best of ITV network programming with high quality news, current affairs and diverse regional programmes which reflect a modern Northern Ireland which is core to the channel's success.
"We are especially pleased to plan the launch of UTV HD on both Sky and DTT by the end of this year, to complement the existing UTV HD service available to Virgin customers in Northern Ireland."