Aquilino Martin "Koko" de la Llana Pimentel III (Tagalog pronunciation: [pimenˈtel]; born January 20, 1964) is a Filipino politician and lawyer who served as a senator of the Philippines from 2011 to 2025. During his tenure, he served as Senate president from 2016 to 2018 and Senate minority leader from 2022 to 2025.
The eldest son of former Senate president Nene Pimentel, the younger Pimentel is the first child of a previous Senate president to hold the office. Pimentel narrowly lost his bid for the Senate in 2007 to Juan Miguel Zubiri, which led to an electoral protest that overturned the initial result, resulting in his proclamation as a senator, taking office in August 2011, four years following the election. Pimentel was subsequently re-elected to the Senate in 2013 under Team PNoy and in 2019 under the Hugpong ng Pagbabago.
Pimentel ran in the 2025 Philippine House of Representatives elections to represent Marikina's first district in the lower house, facing off against Marcelino Teodoro, the outgoing mayor of Marikina. He lost to Teodoro by a wide margin.
Aquilino Martin de la Llana Pimentel III was born on January 20, 1964, in Cagayan de Oro, Philippines. His parents are Aquilino Pimentel, Jr. and Lourdes de la Llana-Pimentel. His father was a lawyer and dean of law at Xavier University at the time of his birth and was elected to the Senate in 1987. His sister, Gwendolyn, was appointed in 2015 as a commissioner of the Commission on Human Rights.
Pimentel earned his Bachelor of Science degree in Mathematics from Ateneo de Manila University and his Bachelor of Laws from University of the Philippines College of Law. He topped the 1990 Philippine Bar Examinations with a score of 89.85 percent.
Legal career and political beginnings
After passing the bar exam in 1990, Pimentel began working as a lawyer at his father's law firm Aquilino Q. Pimentel, Jr. and Associates Law Office in Pasig in 1992, serving there until 1998. He was commissioner on the National Youth Commission, representing Mindanao, from 1995 to 1998. He was a professor for the University of the East College of Law from 2007 to 2010 and also for the JD–MBA Program of the Ramon V. del Rosario College of Business and Far Eastern University Institute of Law from 2006 until his election to the senate in August 2011.
Pimentel ran for Cagayan de Oro city mayor in the 2001 elections but lost to Vicente Emano.
Running in only his second race in the May 14, 2007, senatorial elections, Pimentel was narrowly defeated by Bukidnon Congressman Miguel Zubiri for the 12th and last slot in the Philippine Senate. The narrow margin of 18,372 votes was contested, particularly the votes from the southern Philippine province of Maguindanao, where Pimentel had lost heavily to Zubiri.
In Philippine senatorial elections, the twelve candidates with the highest number of votes nationwide are elected. In the 2007 elections, Pimentel (Genuine Opposition) and Migz Zubiri (TEAM Unity) contested the 12th seat.
In the final tally for the 2007 senatorial elections by the Commission on Elections (COMELEC), Zubiri narrowly defeated Pimentel for the 12th and last seat in the Senate. Zubiri had a total of 11,005,866 votes against Pimentel's 10,984,347 votes. On July 14, 2007, Zubiri was proclaimed as the 12th winning senator.
Claiming fraudulent votes in 22 municipalities of Maguindanao, seven in Lanao del Norte, three in Shariff Kabunsuan, two in Basilan, two in Sultan Kudarat, four in Lanao del Sur, and four in Sulu, Pimentel petitioned the Supreme Court to issue a restraining order against the proclamation of Zubiri. With the vote tied at 7–7, the Supreme Court dismissed Pimentel's petition. But then-Chief Justice Reynato Puno was among the seven justices who favored Pimentel's petition.
On July 14, 2007, Pimentel filed an electoral protest to the Senate Electoral Tribunal (SET). After finding grounds for a recount, the SET proceeded with the protest.
In July 2011, former Maguindanao election supervisor Lintang Bedol and suspended Autonomous Region in Muslim Mindanao governor Zaldy Ampatuan revealed that there was massive election fraud during the 2007 election.
On August 11, 2011, the Senate Electoral Tribunal released the final tally: Pimentel got 10,898,786 votes while Zubiri got 10,640,620. Prior to this, on August 3, 2011, Zubiri resigned from the Senate; however, he reiterated that he was not involved in the 2007 electoral fraud.
On August 11, 2011, Pimentel was proclaimed by the Senate Electoral Tribunal as the rightful winner of the 12th senate seat.
Pimentel was included in the United Nationalist Alliance (UNA) coalition's shortlist of senatorial candidates for the 2013 election. However, citing UNA's senatorial slate now having more than twelve members and the inclusion of his longtime political rival, Migz Zubiri, Pimentel officially declined his spot in the UNA coalition on June 28, 2012. Instead, Pimentel ran under the Team PNoy coalition, composed mostly of supporters of then-President Benigno Aquino III. Pimentel was elected to the Senate of the Philippines, placing eighth with 14,725,114 votes.
Pimentel resigned from his position as Senate President on May 21, 2018, to focus on his reelection bid in the 2019 election and was succeeded by Majority Leader Tito Sotto. Lawyers Ferdinand Topacio and Glenn Chong separately filed two petitions against Pimentel's senatorial bid for serving more than two consecutive terms. COMELEC dismissed the petitions in February 2019 as Pimentel did not fully serve his first term as senator. Pimentel, president of PDP–Laban, was elected as senator and ranked tenth with 14,668,665 votes.