Two pubs in Aylesbury will cut the price of all food and drink by 7.5% to highlight the benefit of a permanent VAT reduction.
The Bell in Market Square and The White Hart on Exchange Street will be serving cheaper products on 23 September.
Both Wetherspoons pubs will serve pints, meals and snacks at reduced prices all day.
The pub group calls this campaign Tax Equality Day, to highlight the tax burden on the hospitality industry.
At present all food and drink in pubs is subject to 5% VAT as a result of the VAT cut by the Chancellor in July 2020.
However, this will change on 1 October, when the VAT rate will rise to 12.5%, with the government's aim of returning VAT to 20%, in stages, in 2022.
By comparison, supermarkets pay zero VAT on food, and are able to use that saving to sell alcohol to its customers at a discounted price.
The White Hart manager, Abbie Cartwright, said: "It is unfair that supermarkets pay zero VAT on food, but pubs and restaurants, in normal circumstances, pay 20 per cent.
"Pubs have been under fantastic pressure for decades due to the tax disadvantages it has with supermarkets.
"Customers coming to The White Hart on Thursday 23 September will find the price of their food and drink is lower than normal.
"However, as a result of the VAT increase to 12.5% on 1 October, we will have to increase food prices.
"Therefore, on Wednesday September 29, we will increase prices on our meals by 50p.
"We urge the Chancellor to create tax equality between pubs and supermarkets by making the current VAT regime for pubs permanent."