Network Rail is set to install two lifts in the existing subway as part of the Government’s Access for All scheme.
They will provide step-free access for passengers using platforms 1 and 2 for the first time.
Campaigners have been calling for a lift to be installed at the station for more than 20 years and the project has often been delayed over the years.
Warwickshire County Councillor John Holland (Warwick West, Labour) who, along with residents, began campaigning for the lift in 2001. Warwick and Leamington MP Matt Western, also joined the campaign.
Work is now due to start in January 2023 and is expected to be complete by the end of the year.
While no train services will be affected by the station improvements, the subway between platforms 1 and 2 will have to be closed for the lifts to be installed.
This means a six-minute diversionary route will be in place for passengers moving between each platform.
A compound for engineers will also be created in the station car park, taking several of the spaces out of use.
The station’s customer toilets will also be temporarily relocated.
To explain more about the plans, Network Rail is inviting residents and businesses to an information event between on Monday November 28 between 3pm and 7pm at the Warwick Arms Hotel in High Street.
Cllr John Holland, said: “There are many people who cannot manage steps and the scheme will provide access for both pedestrians and people who use wheelchairs.
"There are many other people who will benefit, for example people with prams or cyclists taking their bikes on the train.”
Elinor Weymouth, scheme project manager for Network Rail, said: “We’re really pleased to be delivering this important piece of work for passengers in Warwick which will see step-free access between platforms 1 and 2 for the first time.
“There will be some local disruption during the multi-million-pound upgrade which is why we’re holding an information event at the Warwick Arms Hotel so people can find out more.
"I’d urge anyone living or working nearby to come along and meet the project team so we can explain in person how this important work is making journeys better for passengers.”
Network Rail says it is also working closely with Chiltern Railways to cause the least possible disruption to passengers and the local community while work takes places throughout 2023.
Eleni Jordan, commercial and customer strategy director at Chiltern Railways, said: “We are delighted that step-free access between platforms at Warwick station is being installed.
"Alongside Network Rail, we will be in regular contact with local stakeholders and the wider community while these changes take place, as there will be some disruption while these works are completed.
“When the lift installations are complete, it will be a significant improvement to accessibility and customer experience at the station.“