Relations between Germany and the Kingdom of Tonga have traditionally been friendly. As early as 1 November 1876, the German Empire signed a friendship treaty with Tonga. Diplomatic relations with the Federal Republic of Germany have been in place since 1976. The Treaty on Friendly Relations and Cooperation between the Federal Republic of Germany and the Kingdom of Tonga entered into force on 2 January 1978. Germany does not maintain an embassy in Tonga. The German Embassy in Wellington, New Zealand, is responsible for Tonga, while in the country itself Germany is represented by an honorary consul in the capital Nuku’alofa. The Kingdom of Tonga’s mission in London is responsible for Germany.

Bilateral economic relations with Tonga are limited. According to Federal Statistical Office figures, Germany’s imports from Tonga totalled 261,000 euro in 2023; exports to Tonga were worth 124,000 euro.

Germany supports the development of the Pacific island nation through its contributions to the European Union’s Neighbourhood, Development and International Cooperation Instrument (NDICI) (until 2021, the European Development Fund (EDF)). The Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ), together with regional and local partners, is implementing a regional programme focused on adapting to climate change and a regional project aimed at protecting the biodiversity of the oceans and coastal areas, as well as other projects. There are also microprojects in the spheres of infrastructure, education and vocational training, as well as health, the advancement of women and combating domestic violence. Following the volcanic eruption and tsunami in January 2022, Germany has been funding a local assistance project to provide clean drinking water and support community gardens.

Dr Norbert Lammert, then President of the German Bundestag, visited Tonga in September 2016 to mark the 140th anniversary of the friendship between Tonga and Germany.

Tonga is a member of the Group of Friends on Climate and Security in the United Nations, founded by Germany and Nauru.