Miriam Palma Defensor-Santiago GCS QSC (June 15, 1945 – September 29, 2016) was a Filipino scholar, academic, lawyer, judge, author, stateswoman, and politician who served in all three branches of the Philippine government: judicial, executive, and legislative. Defensor Santiago was known for being a long serving senator of the Philippines, an elected judge of the International Criminal Court, and the sole female recipient of the Philippines' highest national honor, the Quezon Service Cross.

In 1988, Defensor Santiago was named laureate of the Ramon Magsaysay Award for government service, with a citation for bold and moral leadership in cleaning up a graft-ridden government agency. After being appointed by President Corazon Aquino as secretary of agrarian reform from 1989 to 1990, she ran in the 1992 presidential election but was defeated in events that involved a car crash injury and power outages during voting process. Defensor Santiago would then serve three terms in the Philippine Senate. After former president Joseph Estrada was arrested on April 25, 2001, she was among the politicians who spoke against EDSA II at pro-Estrada rallies that preceded the May 1 riot near Malacañang Palace.

In 2012, Defensor Santiago was elected as a judge of the International Criminal Court. She later resigned the post, citing chronic fatigue syndrome. On October 13, 2015, Defensor Santiago declared her third candidacy for president of the Philippines in the 2016 election after her doctors from the United States declared her cancer "stable" and "receded" but lost the election. She died from complications from her cancer on September 29, 2016, and was buried days later at Loyola Memorial Park in Marikina. In December 2018, the prestigious Quezon Service Cross was posthumously conferred upon Defensor Santiago, making her the first woman and the sixth person ever to be awarded. Defensor Santiago was known as the "Iron Lady of Asia". She is colloquially known in Philippine pop culture as simply Miriam or MDS and is cited for her dedication to public service in the Philippine government.

Defensor Santiago was born Miriam Palma Defensor in Iloilo City to Benjamin Defensor, a local judge, and Dimpna Palma, a college dean as the eldest of seven children on June 15, 1945. She was class valedictorian in grade school, high school, and undergraduate school. She graduated high school in Iloilo Provincial High School. In 1965, Defensor Santiago graduated with a Bachelor of Arts degree in political science, magna cum laude from the then University of the Philippines College Iloilo. After graduation, she was elected to the Pi Gamma Mu and Phi Kappa Phi honor societies. She proceeded to the University of the Philippines College of Law. There, she was champion in numerous oratorical contests, debates, and topped written examinations. She became the first female editor of the student newspaper, The Philippine Collegian, and was twice appointed Reserve Officers' Training Corps muse. She graduated with a Bachelor of Laws, cum laude, from the University of the Philippines College of Law in Diliman.

Defensor Santiago went on a fellowship to the United States and earned the Master of Laws and Doctor of Juridical Science degrees at the University of Michigan, studying there from 1974 to 1976. Following her fellowship, she studied in numerous schools including Oxford. Harvard, Cambridge, The Hague Academy of International Law, and the Sophia University. In Oxford, she was a research fellow at St. Hilda's College. At Cambridge, she was a research fellow at the Lauterpacht Research Centre for International Law. When she was already a senator, she earned the Master of Religious Studies degree at the Maryhill School of Theology. Her inspiration to become a lawyer and legislator growing up was Arturo Tolentino; she gained experience by being mentored by him.

Defensor Santiago served as a special assistant at the Department of Justice before the martial law under Ferdinand Marcos. In the position, she served as one of Marcos' speechwriters. Defensor Santiago served as Legal Officer of the United Nations High Commissioner for Refugees at Geneva, Switzerland. She was assigned to the Conferences and Treaties Section and gained experience at treaty negotiation and drafting. She resigned her position when her father developed prostate cancer.

In 1983, Defensor Santiago was appointed judge of the Regional Trial Court (RTC) of Quezon City. She was the youngest judge appointed to Metro Manila, exempt from the rule for newcomers to be appointed to provinces outside Metro Manila. The Ramon Magsaysay Award Foundation said she handled a record 50 cases a month by avoiding delays and postponements. She also disposed of the highest number of cases in Metro Manila.

Defensor Santiago's decision against martial law drew public attention. At that time, alleged illegal public assemblies were declared as crimes and were punishable by death. A group of activist students from the University of the Philippines and Ateneo, as well as activists in the film industry, staged a rally in a central business district, and denounced the First Lady for her excesses. This caused Marcos to issue an order which authorized the military to hold suspects indefinitely without bail. Defensor Santiago suspended hearings on all other pending cases and conducted whole-day trials. She eventually ordered the military to allow the students to post bail.