Teodoro Plata (1866 – February 6, 1897) was a Filipino patriot, and a co-founder of the Katipunan, the secret society which sparked the Philippine Revolution against Spanish rule in 1896.
He met Andrés Bonifacio at a boarding house in Manila along with Ladislao Diwa who was then a law student at the University of Santo Tomas. Bonifacio, Diwa and Plata were all freemasons who were inspired by the nationalistic objectives of the Propaganda Movement in Europe.
Plata was a member of La Liga Filipina, which was founded by José Rizal to push for reforms in the Spanish colonial administration. But he agreed with Bonifacio and Diwa who believed that the time was ripe for an armed uprising.
On July 6, 1892, upon learning of Rizal's exile to Dapitan island in Mindanao, Plata, Bonifacio and Diwa decided to form a secret society to prepare for a revolution against Spain. The following day, they met with their friends and fellow freemasons Deodato Arellano, Valentin Díaz and José Dizon at a house in Tondo and established the Katipunan.
In 1892, he served as the secretary of the secret society with Arellano as president, Bonifacio as comptroller, Diwa as fiscal, and Díaz as treasurer.
In 1893, under the presidency of Román Basa, Plata served as councilor and it was at this time that the society organized a women's auxiliary section. One of its first members was Plata's cousin Gregoria de Jesús, who wrote in her autobiography that Plata was Bonifacio's constant companion when he would call at their house in Caloocan to court her.