Demetrio Vallejo (1912 – December 24, 1985) was a railroad worker and union activist from Tehuantepec, Oaxaca, Mexico. Vallejo began working as a railroad employee in 1928, later joining the Partido Comunista Mexicano (PCM) in 1934. Vallejo was eventually promoted to Regional Director of the PCM in Oaxaca, however later expelled in 1946. In 1946, Vallejo joined the Unified Socialist Action (Spanish: Accion Socialista Unificada) and later the Mexican Worker-Peasant Party (Spanish: Partido Obrero-Campesino Mexicano (POCM) at its founding in 1950. Vallejo was a primary leader of the Mexican railroad strikes of 1958–59.
On June 26, 1958, the Union of Railroad Workers of the Mexican Republic (Spanish: Sindicato de Trabajadores Ferrocarrileros de la Republica Mexicana) (STFRM) Local 13 of Matias Romero, Oaxaca, began a series of escalating strikes, beginning at 2 hours in length, then expanding up to 8 hours, before finally calling a general strike. The STFRM followed Vallejo's call for higher wages, an increase of 350 pesos a month, this became known as "Plan of the Southeast." The strikes were supported by the workers, however failed to gain support of its own union leader, Ortega Hernandez. The strikes began as the demands were not met. On June 26, 1958, the first strike lasted 2 hours and was participated in by almost 60,000 members. The following day on June 27, a 4-hour strike was held, and on June 28, a 6-hour strike. The strike on June 28 was not only of railroad workers, but found the support of petroleum workers, teachers, and students. President Adolfo Ruiz Cortines stepped in before the final steps of strike escalation. Cortines proposed a middle ground between the offer of the railroad, 200 pesos, and the lowered demand by the union of 250 pesos, settling on 215 pesos which was accepted by all parties.