Thomas Esang "Tommy" Remengesau Jr. (born 28 February 1956) is a Palauan politician. He served as the Palauan president between 2001-2009 and 2013-2021. He served as a Senator in the Palau National Congress between his two administrations. In sum, Remengesau was elected Vice-President of Palau in 1992 and 1996, then president in 2000, 2004, 2012 and 2016.

Intending to make Palau less dependent upon United States aid, Remengesau has promoted the expansion and growth of tourism in Palau with the slogan "Preserve the Best and Improve the Rest". The "best" refers to Palau's especially bountiful and diverse marine water resources surrounding the islands, and, as a venue of underwater attractions, its reputation among the very top in the world. In foreign affairs, Remengesau has actively advanced Palau's presence in the United Nations, elevating Palau to leadership among the international community through such environmental initiatives as the Micronesian Challenge. He is also a leader among South Pacific nations in advocating awareness of global warming and its effects in the South Pacific Region.

In 2024, Remengesau ran for a fifth term in office, but decisively lost the election to incumbent Surangel Whipps Jr., making it the first election he ever lost.

Remengesau was born in Koror, Palau. His father was Thomas Remengesau Sr., who was District Administrator of Palau during the Trust Territory era, as well as Minister of Justice, Vice President, and briefly President of Palau. His mother, Ferista Esang Remengesau, also served as First Lady of Palau. Remengesau was educated at Grand Valley State University in Allendale, Michigan, in the United States, graduating from there in 1979.

At 28 years old, Remengesau targeted the youth voting bloc of Palau and successfully lobbied for their support, in the process becoming known as one of the forefront advocates for the youth of Palau. Remengesau was then elected in 1984 to the Palau National Congress (Olbiil Era Kelulau), carried by the youth and a grassroots campaign to become the youngest senator in the nation's history at the age of 28. In 1992, he was elected Vice President of Palau and served two terms. He held the additional portfolio of Minister of Administration of Palau. In 2000, with the support of outgoing President Kuniwo Nakamura, he won the presidential election, defeating ex-senator Peter Sugiyama by a margin of 52% to 46%. He easily won re-election in 2004, defeating Polycarp Basilius by a margin of 66.5% to 33.5%, in a race dogged with rumors of improper financial influence from Taipei and Beijing.^{[citation needed]}

In December 2003, following the DePaiva family murders, Remengesau expressed shock at the killings and offered apologies to the surviving daughter and her family on behalf of Palauans, saying that the country had never seen a crime like that before, urging Palauans to fight drug abuse and uphold service to the family and society.

Remengesau announced in 2008 that he would seek a senatorial seat in the Senate of Palau in the 2008 general election. He came in 11th in the election.

Remengesau was succeeded by President Johnson Toribiong on January 15, 2009.