For the first time, a major American retailer is offering a dedicated line of decorations for the holiest month on the Islamic calendar: Ramadan, which culminates in the Eid al-Fitr celebration.

The retailer, Party City, which has about 850 locations, mostly in the United States, was motivated to create the items because customers kept requesting them, Ryan Vero, the company’s president of retail, said this week. “We are always seeking insights from our store teams who are engaging with our customers every day,” said Mr. Vero, who called these customers underserved when it comes to party supplies.

Party City’s Ramadan items, which were designed by its internal product innovation team, have been selling well online — many items have sold out — and will be available by Saturday in some stores in cities like New York, Los Angeles and Sugar Land, Tex.

The announcement is welcome news to many Muslims gearing up for the holiday, which begins on May 16 and ends at sundown on June 14 — the start of the Eid al-Fitr party that goes through June 15.