Milk made history as the first openly gay man to hold political office in California when he was elected to the San Francisco Board of Supervisors in 1977. He was assassinated, along with San Francisco mayor George Moscone, on Nov. 27, 1978.
Milk will be the first openly LGBT elected official to be featured on a U.S. stamp.
In 2009, he was posthumously awarded the Medal of Freedom by President Barack Obama.
The first-day-of-issue dedication ceremony on May 22 coincides with Harvey Milk Day in California.
The stamp image will be previewed at a later date and a public dedication ceremony will take place in San Francisco May 28.
The non-denominated “forever” stamp will sell for the current first-class postage rate of 49 cents.