Roy Henry Cullen died Friday at his River Oaks home in Houston.
He was the grandson of legendary oilman Hugh Roy Cullen.
No cause of death has been announced.
Cullen was 84.
He was born on October 29, 1929, to Roy Gustav Cullen and Katherine Thompson Cullen.
He studied engineering at Rensselaer Polytechnic Institute in Troy, New York and learned the oil business from his grandfather.
He was an officer and director of Quintana Petroleum Company for many years.
Cullen was also an original board member of Cullen Bank.
He was a well-known philanthropist.
The Cullen Foundation that he chaired from 1998 until his death raised money to fight Parkinson’s Disease.
His daughter Lillie died of the disease in 2004 at age 53. She was first diagnosed with Parkinson’s at age 38.
Roy Cullen is survived by his wife, Mary Garcia Cullen, four children, brother Harry Cullen, sister Cornelia Long, and many extended family members.