From September 2018 to mid-November 2018, Rangers FC also helped fix the retail price of adult home short-sleeved replica shirts.
In response to the findings, the CMA has fined Elite Sports £459,000, while Rangers FC has received a £225,000 penalty.
The three companies were found to have conspired to stop JD Sports from undercutting the retail price of the shirt on Elite’s Gers Online store.
As part of the agreement, JD raised its price by almost 10% from £55 to £60 to make the prices similar to those charged by Elite on Rangers’ website.
CMA enforcement executive director Michael Grenfell said: “At a time when many people are worried about the rising cost of living, it is important that football fans are able to benefit from competitively priced merchandise.
“Instead, Elite, JD Sports and, to some extent, Rangers, worked together to keep prices high.
“Today’s decision sends a clear message to football clubs and other businesses that illegal anti-competitive collusion will not be tolerated.”
Elite Sports was the official manufacturer of Rangers-branded clothing at the time of infringement, as well as selling Rangers-branded products directly through its Gers Online store.
JD Sports was the only UK-wide major retailer selling the products at the time.
Last month, the retailer agreed to sell Footasylum to German asset management firm Aurelius Group for £37.5m.