The popular take-away currently takes pride of place in Bishop Weald House on the corner of Worthing Road and Bishopric. This year marks its 25th year in the town.
The chain told the County Times this week the branch would be closing.
Neighbouring businesses The Entertainer and Argos have confirmed their stores do not face the same fate.
John O’Dwyer, McDonald’s Horsham franchisee, said: “I am sad to announce that our restaurant on Worthing Road will close on Sunday July 27.
“I am pleased to say that all staff have been offered transfers to my other restaurants and would like to thank all of our customers who have supported the restaurant over the years.”
A spokesman added there were currently no plans to open another branch in Horsham.
The closure comes as Horsham District Council considers plans by developer Westrock to renovate Bishop Weald House and redevelop the area west of Albion Way.
In its £35m ‘West End’ scheme, Westrock plans to partly demolish and redevelop Bishop Weald House to provide 53 new apartments above the shops. New retail units would be built fronting Albion Way.
Robin Barton, development director of Westrock said: “The McDonald’s lease lapses in August. That’s a fact of their lease. It’s not something that has been brought about.
“We are looking at other options for the building. It’s not being renewed because we are looking at giving it a new lease of life.
“Sometimes when there’s change, when you want to move a town on with a new development, there’s a certain amount of things having to move around. It will be a better town centre after everything has settled down.”
Both The Entertainer and Argos have said this week said they would be staying in the town.
Gary Grant, managing director for The Entertainer, said: “It’s been really strong for us in Horsham. The only other stores we have around there are Crawley and Brighton, so Horsham nestles between the two.
“We are definitely not closing. It’s a great location and we are well supported by the local community.”
A spokesman for Argos said: “Argos is aware of a planning application that has been submitted to convert the upper floors of Bishop Weald House for residential use, and the ground floor offices fronting onto Albion Way into retail use.
“The premises occupied by Argos are not affected by the proposed development and there are no plans to close the store.”
The Westrock development also includes the redevelopment of land west of Albion Way, for which it has already received planning permission.
The Lifestyle Ford car dealership located there announced earlier this month 100 of its employees on that site will be relocating to its new site on Guildford Road and seven jobs will be lost.
The Horsham Bowls Club, also on the site, has already moved to Holbrook Tythe Barn. The area will become the new home of the Horsham Waitrose store, and a John Lewis at Home.
The existing Waitrose store and staff in Piries Place would relocate, with an added 50 jobs provided on top of the 120 already employed.