A small but dedicated group of Georgetown University students gathered in front of the administration building in Northwest Washington yesterday afternoon to demand that their school withdraw its investments in companies with financial holdings in South Africa.

Organizers said the protest was called to coincide with a meeting of the school's Committee on Investment and Social Responsibility, which was discussing the issue of divestment yesterday, and to show support for apartheid protesters at Columbia University, where about 300 students continued to defy a five-day-old court order barring them from barricading the entrance to a campus building.

Meanwhile, about 250 students congregated near the front steps of Georgetown's administration building, Healy Hall, and about 100 took part in the protest by chanting slogans, carrying signs and cheering speakers.

"There is a note of shame and cloud of disgust over this university," said Kathy McShea, a senior majoring in American government and cofounder of The Student Coalition Against Apartheid and Racism, an organizer of the protest.

McShea said that Georgetown students had a special responsibility to protest apartheid because of the staunch support given to the Reagan administration's policy of "constructive engagement" by two of the school's former professors, Assistant Secretary of State for African Affairs Chester A. Crocker and former U.S. ambassador to the United Nations Jeane Kirkpatrick.

McShea said that about $10 million of Georgetown's $80.5 million endowment is invested in companies that have financial holdings in South Africa.

Anne Klass, a spokeswoman for Georgetown, said that the school's Committee on Investment and Social Responsibility will make a recommendation to the university's board of directors on the divestment issue "after gathering all pertinent data."

Meanwhile, about 65 persons demonstrated yesterday outside the South African Embassy on Massachusetts Avenue NW to protest that country's racial segregation, D.C. police reported. They said that five demonstrators were arrested, bringing to 1,876 the number of people arrested in the 4 1/2-month-old protest.