Robert T. Stafford, the long-serving Republican senator from Vermont who played such a major role in shaping the guaranteed-student-loan program that his Senate colleagues named the program for him, died this morning at the age of 93.

The guaranteed-loan program, the largest source of federal student loans, offers tens of billions of dollars in low-interest loans to millions of college students every year. Until earlier this year, the interest rate on those loans had fluctuated with the financial markets, but a new deficit-reduction law allowed the rates to rise to a higher fixed level, at 6.8 percent. The Democrats who will take control of Congress next month are expected to push for a sharp cut in that interest rate.

Senator Stafford, who served from 1971 to 1989, was also known for his strong advocacy of environmental legislation — another mark of his moderate or even liberal views on social issues that, two decades later, have become all but extinct among Republicans elected to national office from New England.

Mr. Stafford’s views on education and environmental policy often brought him into conflict with his more-conservative Republican colleagues and with Republican policy makers in the White House.

In 1985, as chairman of the Senate Education Committee, Mr. Stafford assailed comments by the new secretary of education, William J. Bennett, who in endorsing President Ronald Reagan’s plan for student-aid cuts, said needy students should now consider “divestitures of certain sorts — like a stereo divestiture, an automobile divestiture, or a three-weeks-at-the-beach divestiture.”

A year later, Senator Stafford helped oversee a renewal of the Higher Education Act that largely fended off such Reagan-administration proposals.

The Associated Press has published an obituary.