A bomb exploded in the Liberal Party campaign rally in Plaza Miranda, Manila, Philippines with several anti-Marcos political candidates injured.

The Plaza Miranda bombing (Filipino: Pambobomba sa Liwasang Miranda) occurred during a political rally of the Liberal Party at Plaza Miranda, Quiapo district, Manila, the Philippines on August 21, 1971. It caused nine deaths and injured 95 others, including many prominent Liberal Party politicians.

The Liberal Party (Filipino and Spanish: Partido Liberal), abbreviated as the LP, is a liberal political party in the Philippines.Founded on January 19, 1946, by Senate President Manuel Roxas, Senate President Pro-Tempore Elpidio Quirino, and former 9th Senatorial District Senator José Avelino from the breakaway liberal wing of the old Nacionalista Party, the Liberal Party remains the second-oldest active political party in the Philippines after the Nacionalistas, and the oldest continually-active party. The Liberals served as the governing party of four Philippine presidents: Manuel Roxas, Elpidio Quirino, Diosdado Macapagal, and Benigno Aquino III. As a vocal opposition party against the dictatorship of Ferdinand Marcos, the party reemerged as a major political party after the People Power Revolution and the establishment of the Fifth Republic. It subsequently served as a senior member of President Corazón Aquino's UNIDO coalition. Upon Corazón Aquino's death in 2009, the party regained popularity, winning the 2010 Philippine presidential election under Benigno Aquino III. The Liberal Party returned to government, serving from 2010 to 2016. However, this was the only instance of the party winning the presidency since the Marcos dictatorship, as they lost control of the presidency to Rodrigo Duterte of PDP–Laban in the 2016 presidential election and became the leading opposition party; however its vice presidential candidate Leni Robredo won, narrowly beating the second candidate by a small margin.The Liberal Party is currently the political party of the Vice President of the Philippines. As of the 2019 midterm elections, the party is still the primary opposition party of the Philippines, holding three seats in the Senate. The Liberals are the largest party outside of Rodrigo Duterte's supermajority, holding 18 seats in the House of Representatives. In local government, the party holds two provincial governorships and five vice governorships.

The Liberal Party remains an influential organization in contemporary Philippine politics. With center-left positions on social issues and centrist positions on economic issues, it is commonly associated with the post-revolution, liberal-democratic status quo of the Philippines in contrast to authoritarianism, neoconservatism, and socialism. Aside from presidents, the party has been led by liberal thinkers and progressive politicians including Benigno Aquino Jr., Jovito Salonga, Raul Daza, Florencio B. Abad Jr., Franklin Drilon, and Mar Roxas. Two of its members, Corazón Aquino and Leila de Lima, have received the prestigious Prize for Freedom, the highest international award for liberal and democratic politicians since 1985. The Liberal Party is a member of the Council of Asian Liberals and Democrats and the Liberal International.