Peace Boat (ピースボート, Pīsu Bōto) is a global non-government organization headquartered in Japan established for the purpose of raising awareness and building connections internationally among groups that work for peace, human rights, environmental protection and sustainable development. "Peace Boat" may also refer to one of the ships embarking on a cruise under the Peace Boat organization. Since its founding in 1983, the Shinjuku, Tokyo based organization has launched more than 100 voyages. These cruises, the main operation of the Peace Boat organization, are on average carried out at least three times a year. Peace Boat, described by the San Francisco Chronicle as a "floating university of sorts", offers educational opportunities aboard, with conferences related to global events. They also provide humanitarian aid at their various stops and visit local organizations.

Besides the international voyages, Peace Boat carries out a number of other projects seeking justice in various international realms such as a campaign for the abolition of land mines, the Global Article 9 Conference to Abolish War, the Global Hibakusha Forums, and others onboard and in ports. Peace Boat also acts as the Northeast Asia regional secretariat of the Global Partnership for the Prevention of Armed Conflict, and is member of ICAN (International Campaign to Abolish Nuclear Weapons), having played a significant role in negotiations to strengthen the Treaty on the Prohibition of Nuclear Weapons, which was awarded the Nobel Peace Prize on December 10, 2017. Peace Boat is an NGO in Special Consultative Status with the Economic and Social Council of the United Nations and a committed campaigner for the Sustainable Development Goals (SDGs).

In 1983, Yoshioka Tatsuya and Kiyomi Tsujimoto, then students of Waseda University, initiated Peace Boat in answer to Japanese history textbook controversies. With the assistance of like-minded students, they organized the first voyage. Peace Boat has since visited more than 270 ports with over 70,000 participants.

During the first six years after it was founded, Peace Boat ran one- to two-week long cruises to various Asian countries around Japan at the rate of one per year. Time on the boat was used to hold lectures and events with guest speakers invited from the countries to be visited. When at port, international exchange events were carried out with local NGOs and student groups. This became the foundational style for which the rest of the cruises would be based on.

In 1990, the 10th Peace Boat cruise marked the beginning of the circumnavigational cruise series. During the cruise, the Gulf War broke out and the ship encountered a US aircraft carrier in the Red Sea. After the success of first round-the-world cruise, Peace Boat continued them on a regular basis.

In 1991, after the fall of the Soviet Union, Peace Boat set out to the Kuril Islands with the notion of a citizen's diplomacy mission, stopping at Iturup, Kunashir, and Shikotan islands. There were homestays and tours. This was the first trip made to these islands without a visa by an NGO from Japan.

Over the past 30 years, Peace Boat has organized over 100 voyages, including more than 60 around-the-world voyages, carrying over 70,000 participants to over 270 ports. The participants range from toddlers to people in their 90s, from many different countries and professions. The organization was nominated for the Nobel Prize in 2008.

During its history, Peace Boat has chartered many different vessels.