The current forbearance agreement expired on June 30.
in a statement to CNN Business, Yum Brands said that the bankruptcy filing "was expected" and that it remains supportive of the company.
NPC International franchises 1,227 Pizza Hut restaurants, out of 7,100 nationwide, and 393 Wendy's restaurants.
NPC has 7,500 full-time employees and about 28,500 part-time employees.
The company said that it would be looking to unload "some or all" its Wendy's restaurants as part of its debt restructuring, giving it a "smaller, more profitable footprint of restaurants."
NPC said it would immediately begin to market the sale of its Wendy's restaurant assets. The restaurants will be marketed "on a single, going-concern basis as individual, market-based transactions," the company said.
The Pittsburg, Kan., company, which has been operating Pizza Hut franchises since 1958, said headwinds like "uncertainty on trade and commodities" and "drastic shifts in the labor market increasing pressure on hiring wages," were hurting the Pizza Hut brand.
NPC said Pizza Hut faced "deteriorating brand image" due to a crowded pizza market and the reluctance of Yum Brands to "invest in brand development."
The company filed for Chapter 11 protection with the U.S. Bankruptcy Court in the Southern District of Texas. The company is represented by Alfredo R. Perez of Weil Gotshal & Manages.
Yum Brands shares at last check slipped 0.3% to $86.62,