Work will start on Monday 7 September to replace the traffic lights at the junction of Trinity Street, Southolme and Colville Terrace.
The old traffic lights at the junction – outside the town's Tesco superstore – will be replaced with new, ultra-low voltage equipment to drastically reduce the energy consumption and carbon footprint of the lights.
Lights will also be upgraded at the pedestrian crossing on Trinity Street between Tesco and McDonald's.
Work is expected to take six weeks, during which time there will be three-way temporary traffic lights and a road closure on Southolme Road. Local diversion routes and temporary pedestrian crossings will be in place.
During the works, Trinity Street will be resurfaced from the junction with Southolme to the junction with Albert Terrace. Resurfacing will take place overnight to reduce traffic disruption on dates to be confirmed.
Anthony Gent, principal engineer in the traffic signals team at Lincolnshire County Council, said:
"Just as your phone or laptop might need replacing as technology moves on, the same is true for traffic lights. They have a longer lifespan than most tech, but these in Gainsborough have reached the end of their life. We want our roads to be as safe as possible for all our roads users, so we're bringing the lights at this junction and crossing up to standard.
"Thanks to residents in Gainsborough for bearing with us whilst we make these upgrades."