Valentín Toribio Demetrio Agustin Paniagua Corazao (23 September 1936 – 16 October 2006) was a Peruvian lawyer and politician who briefly served as 55th President of Peru from 2000 to 2001.

Due to Fujimori shortening his presidential term in order to expire on 28 July 2001, Paniagua's main task was to oversee the new elections.

In August 1955, as a student leader, he was one of the founders of the Frente Universitario Reformista Independiente, a social-Christian reform organization, opposed to landowners' rights, to the communists and to the APRA.

Paniagua became a member of the Christian Democrat Party (PDC), which was best aligned to his Roman Catholic and reformist ideals.

In 1966, a section of the PDC led by the then-mayor of Lima, Luis Bedoya Reyes, cut ties with the leadership of Héctor Cornejo Chávez and founded the Partido Popular Cristiano (PPC).

The coup d'état of General Juan Velasco Alvarado on 3 October 1968, sent Paniagua out of Congress and for some years he was left out of politics.

His loyalty to the constitutional legality of Belaúnde led him to abandon the PDC on 27 July 1974, in protest of its acceptance of the military government.

The defeat of AP in the 14 April 1985 elections and arrival to power of Alan García's APRA sent Paniagua to the opposition.

Over the following five years he remained a strong foe of the government and worked as a prestigious lawyer in academic and political circles, as well as a professor of constitutional law at the universities of San Marcos, Femenina del Sagrado Corazón and Pontificia Católica.

Paniagua had to work with Fujimori's Peru 2000 party in Congress, since it still was the most important political organization (even though it no longer had a majority).

Paniagua was also involved in the repeal of much of the anti-terrorist legislation enforced by Fujimori, which included trials by faceless judges and juries.

He declined this in order to participate in the 2006 election, as Frente de Centro's presidential candidate in an unsuccessful campaign, in which he came in fifth place, receiving 5.75% of the vote.