The event will feature live ethnic music and a program including short speeches from members of such communities as the Chinese, Japanese, Korean, Latino and Ethiopian.
San Francisco's mayor, Willie Brown, will speak and Jewish community leader John Rothmann will serve as master of ceremonies.
Portsmouth Square is bordered by Washington, Clay, Kearny and Grant Streets. In case of rain, the rally be moved to the Chinese Cultural Center, 750 Kearny St.
For information, call Felice Sheramy at (415) 957-1551 or Eva Seligman Kennard at (415) 585-1400.