Brown University announced yesterday that it would raise undergraduate tuition to $1800 for the year 1964-65. With the increase, Brown will join Yale and Dartmouth as the Ivy League's three most expensive schools.

The tuition rise at Brown follows closely a number of similar rises at other Ivy League schools last spring. Harvard announced that it would increase its tuition to $1760 beginning in 1964. Last fall both Cornell and Columbia upped their tuitions to $1700.

At the beginning of this year, Brown trustees also raised the college's uniform room rentals $70, bringing total room and board expenses to $970. According to sources at Brown, it was this rise that surprised students most.

The University of Pennsylvania and Princeton University are the only Ivy League schools which have not raised their tuitions during the past year. Penn currently charges $1630, Princeton $1630. Yale University and Dartmouth both announced last spring increases to $1800 for 1964-1965.

The Harvard tuition increase is the first hike since an even greater rise three years ago. At that time, the fall of 1961, the tuition was raised from $1250 to $1520, the present figure. The new increase will go into effect at the begining of the fall term, 1964.