Aurelijus Rūtenis Antanas Mockus Šivickas (Spanish pronunciation: [anˈtanas ˈmokus]; born 25 March 1952) is a Colombian mathematician, philosopher, and politician. He has a master's degree in philosophy from the National University of Colombia, and a Honoris Causa PhD from the University of Paris.

He is the son of Lithuanian immigrants. He left office as the president of the National University of Colombia in Bogotá in 1993, and later that year ran a successful campaign for mayor. He proceeded to preside over Bogotá as mayor for two (non-consecutive) terms, during which he became known for springing surprising and humorous initiatives upon the city's inhabitants. These tended to involve grand gestures, including local artists or personal appearances by the mayor himself—taking a shower in a commercial about conserving water, or walking the streets dressed in spandex and a cape as Supercitizen. On 4 March 2010, he was elected in a public consultation as the Colombian Green Party candidate for the presidential election in 2010.

On 4 April 2010, Antanas Mockus chose Sergio Fajardo, former mayor of Medellín, as his vice-presidential running mate. On 9 April 2010 he announced that he had been diagnosed with Parkinson's disease. He told La W radio: "The prediction is that this will not affect my mental activities. I think it is absolutely fitting to tell the people about the diagnosis and about the prognosis—which is 12 years or more of normal life thanks to medication." Mockus finished second in the polling, leading to a runoff election with Juan Manuel Santos, which Santos won. Mockus resigned from the Green Party in June 2011 because he opposed its Bogotá mayoral candidate being supported by former right-wing President Álvaro Uribe.

He became Senator of the Republic of Colombia in July 2018, after being the second candidate with the most votes in the legislative elections held on March 11, 2018. He is also the president of the Corporación Visionarios por Colombia (Corpovisionarios), center of thought and non-profit action that investigates, advises, designs and implements actions to achieve voluntary changes in collective behavior.

Mockus was born in Bogotá. He holds a 1972 Bachelor of Arts degree in mathematics from the University of Burgundy in Dijon, France and a 1988 Master of Arts degree in philosophy from the National University of Colombia. He has been a professor and researcher at the university since 1975 and has served as its vice president (1988–1991) and president (1991–1993). As its president, he contributed to the formulation of the Colombian Constitution of 1991, focusing on educational issues. In a notable 1993 incident, when confronted with a disruptive group of students, he mooned them. He later explained his action by saying "Innovative behavior can be useful when you run out of words", and linked it to philosopher Pierre Bourdieu's concept of "symbolic violence." He resigned as University president during the aftermath but gained a higher public profile that benefited his subsequent run for the mayorship.

In 1995, he was elected Mayor of Bogotá. Under Mockus's leadership, Bogotá saw improvements such as: water usage dropped 40%, 7,000 community security groups were formed and the homicide rate fell 70%, traffic fatalities dropped by over 50%, drinking water was provided to all homes (up from 79% in 1993), and sewerage was provided to 95% of homes (up from 71%). When he asked residents to pay a voluntary extra 10% in taxes, 63,000 people did so. His market-oriented social policies were much less successful. Poverty and unemployment levels were high throughout his tenures and continue to be a pressing issue in Bogotá's social life.

Famous initiatives included hiring 420 mimes to make fun of traffic violators, because he believed Colombians were more afraid of being ridiculed than fined. He also put in place one "Night Without Men", on which the city's men were asked to stay home for an evening to look after the house and the children while the women went out. The city sponsored free open-air concerts, bars offered women-only specials, Ciclovia and the city's women police were in charge of keeping the peace. Amassing political support mainly from Bogotá's middle and upper classes, he has been much less successful attracting voters in the national level.

During Mockus' unsuccessful presidential bid in 1998, Enrique Peñalosa replaced him as mayor. Peñalosa worked in a similar way instituting popular new bike paths and bus systems. When Mockus ran again for the 2001 mayorship, he held a ceremony in a public fountain "to ask forgiveness for leaving the mayor's office in an unsuccessful bid for the presidency." The impact of Mockus and Peñalosa on the development of Bogotá is described in a documentary film released in October 2009 with the title CITIES ON SPEED – Bogotá Change.