Terms of the deal were not disclosed.
Murphy Cap & Gown Co., the nation's leading religious robe company, will be added to Herff Jones' cap and gown division and retain its St. Petersburg headquarters, Herff Jones announced last week.
Murphy has about 200 workers and has been in business 95 years.
Herff Jones Vice President of Human Resources Michael Williams said the addition will not affect operations in Indianapolis.
However, Williams said that while Herff Jones is better known for its graduation gowns, it also has long sold religious robes.
"We've acquired a company that's been a very close competitor to our company, highly respected," Williams said. "It's a logical fit for our company, and it improves our existing product lines at the same time."
A Murphy official would not comment.
Based at 4501 W. 62nd St., Herff Jones is owned through an employee stock plan, and has 4,000 workers at 19 U.S. plants.
It employs about 500 in Indiana at its headquarters and plants that print graduation announcements and make maps, globes and other educational materials.