Andreas du Plessis de Richelieu (24 February 1852 – 25 March 1932) was a Danish naval officer and businessman who became a Siamese admiral and minister of the navy.

Botanist Ernst Johannes Schmidt in 1901, circumscribed Richelia, which is a genus of nitrogen-fixing, filamentous, heterocystous and cyanobacteria and named in Richelieu's honour.

He had a younger brother named Louis August du Plessis de Richelieu [da] who was born on 8 January 1856.

Andreas would then sail from Denmark to Bangkok via Singapore and with assistance from the Danish consul, he was given an audience by Chulalongkorn on 3 April 1875.

However to Siam's navy being small, Andreas occupied himself with other projects such as establishing railways and tramlines in Bangkok.

They also established the Oriental Provision Store which became the main supplier of goods to the Marine forces and the Vesatri due to Andreas' role as superintendent.

In 1892, they would delivered a new royal yacht called the Maha Chakri which Hans Anderson sailed from Scotland to Siam.

[4] In 1891, he was chosen by Chulalongkorn as an envoy on a private diplomatic mission to France, Denmark and the Russian Empire along with the king's brother Prince Damrong Rajanubhab.

As Chulalongkorn continued to modernize his country, the EAC paid for concessions in industries such as teak tree logging.

[4] He would also lead the construction of the first electric tramline in the country which ran 18 km from the Royal Palace to Klong Toey, with Fleuron Jacobsen becoming the project's manager.

[8] His younger sister Louise Frederikke Caroline du Plessis de Richelieu was born on 1 June 1854 and his younger brother Louis du Plessis de Richelieu was born on 7 January 1856.