Mrs Cox, 41, who was shot and stabbed in Birstall, West Yorkshire last year, was a fan of the theatre and particularly enjoyed Les Miserables.
A youth theatre group led by West End professionals will put on its first show in Batley later.
Kim Leadbeater, Mrs Cox's sister, said she would have been "very proud".
The school edition adaptation, which is being performed entirely by people from the newly-formed Batley and Spen Youth Theatre Company, will feature costumes and props from the original West End production.
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It is being led by director Nick Evans, who has guided productions such as Billy Elliot, the Musical and Mary Poppins as well as producer Donna Munday, who has worked on Hamlet, Funny Girl and Bend it Like Beckham.
Mr Evans said the project was intended to show people in the community that the rest of the country cared about what had happened.
"We wanted to say to people who had been in that town who had been in that community on that day, that they weren't alone, that actually there was a future."
Ella Schofield, 17, who plays the role of Cosette, described the costumes, as "sick".
"The most exciting thing about them, despite how gorgeous they are, is if you look in the labels you can see which actors have worn them."
The musical, which runs until Saturday, is being performed in a pop-up theatre space donated by Oxfam, where Mrs Cox previously worked for eight years.
More than 100 youngsters will pay tribute to murdered MP Jo Cox by staging a performance of her favourite musical in her constituency.