Cayetano César Concepción Martínez, (1909 – 1974), was a Puerto Rican musician and composer, who brought the music of his native land to Latin American ballroom dancing, and ballrooms all over the world. He popularised the plena as a Latin song style.

César Concepción was born in Cayey, Puerto Rico, and was a noted composer of his time, writing music based on contemporary Puerto Rican scenes and vistas. He wrote several plenas, mambos, and salsa songs to honor cities such as San Juan, Mayagüez, Ponce, Yauco, Salinas, and Santurce. In addition, he directed his own orchestra for 25 years.

He died in Río Piedras, Puerto Rico. The orchestra continues to perform in the present day, often playing in prominent Puerto Rican social circles.