The Prime Minister's Office says Johnston will travel to Los Angeles, San Diego, San Francisco and Seattle between April 28 and May 2.
In his first official visit to the U.S. West Coast, the Governor General will meet government representatives, business leaders, researchers and innovators.
The PMO says the trip is intended to strengthen bilateral relations, including commercial, educational and philanthropic ties.
This will be Johnston's third trip to the United States since taking office.
In 2012, he went to Hawaii to visit Canadian Forces members taking part in a naval exercise and in 2013 he travelled to Boston and New York City for talks with business and financial leaders.