Victory over Japan Day marked the end of the conflict, four months after fighting ended in Europe.
It is estimated that there were 71,000 British and Commonwealth casualties of the war against Japan, including more than 12,000 prisoners of war.
More than 2.5 million Japanese military personnel and civilians are also believed to have died.
Commemorations for VJ Day are being held around the world.
Japan's Prime Minister Shinzo Abe sent an offering to a controversial war shrine in Tokyo to mark the occasion, but did not attend in person.
However, two of his ministers did visit the Yasukuni Shrine, in a move that is likely to anger China and South Korea.
Fourteen leaders who were later convicted by the Allies as war criminals are commemorated at the shrine, which both China and South Korea view as a symbol of Japan's military aggression during the war.
What is VJ Day?
On 15 August 1945, Japanese Emperor Hirohito addressed the nation and announced an end to the fighting. The country's official surrender was signed on 2 September the same year.
Victory in Europe (VE) Day took place on 8 May following Germany's surrender, but the war continued in the Asia-Pacific region for months.
The end of the conflict in Japan came days after the US dropped nuclear bombs over the cities of Hiroshima and Nagasaki on 6 and 9 August.
More than 200,000 people are believed to have been killed.