Hayley Walker took the expensive gown to Elite on Kirkgate, in Wakefield, around February 2019, months after her big day, but has not seen it since.
Her veil and thigh garter were also both sent to the dry cleaners, both of which have enormous sentimental value.
The veil belonged to her mum, while the garter was made from part of the veil and her late grandfather's blue tie.
The mother-of-two, who lives in the Barnsley area, tried to take the items to her local dry cleaners, but was told it required a specialist clean, and was advised that Elite would be the closest business with the capability to carry out the work.
Having driven to Wakefield, which she admits to not being familiar with, she eventually located the shop which was below the Manor House residential tower block in the city centre.
She paid £100 for the clean up front and was given a ticket.
However, she never heard back from the shop and after trying to contact them months later, still had no response.
The country was then put into lockdown in March 2020, and once restrictions began to ease, she found out the shop had closed for good.
Hayley, who is 31 and is expecting her third child, said: "I cried my eyes out, I'm just devastated because it means everything to me. They never contacted me to say it was ready.
"I have no idea when it even closed down, I've been searching online and it looks like it might have been about October 2020.
"I have no idea what has happened to my dress, I'm hoping that it's still there if they've gone bust."
Hayley married her fiancé in September 2018 at Whirlowbrook Hall in Sheffield. The ivory-coloured lacy dress cost around £1,300, but Hayley says it has far more sentimental value.
She said: "It cost an arm and a leg, but to me it's priceless. It's a lifetime memory, I never had any intention of selling it, I always wanted to keep it.
"I just want it back. I have a daughter of my own now and it would be nice to give to give it her for when she is older. I was also wanting to wear it to renew my vows for out 10-year anniversary."
Anyone who may know what happened to the dress, the veil or the garter can email [email protected] or call Nick on 07803 506082.