WASHINGTON (AP) _ President Reagan and Japanese Prime Minister Noboru Takeshita will sign an agreement on science and technology cooperation during the Toronto economic summit, it was announced Friday.

White House spokesman Marlin Fitzwater said the agreement ''provides for joint initiatives to strengthen the science and technology relationship between the United States and Japan, based on the principles of mutual and equitable contributions and benefits, and comparable access to each other's government-sponsored research establishments.''

Reagan and Takeshita, along with the leaders of Britain, France, West Germany, Italy and Canada, will meet from Sunday until Tuesday.