| Reinaldo Paniagua Diez | |
| State Senate: | Puerto Rico |
| District: | At-large |
| Term Start: | 1985 |
| Term End: | 1989 |
| Order2: | 7th |
| Office2: | Secretary of State of Puerto Rico |
| Governor2: | Carlos Romero Barceló |
| Term2: | 1977-1979 |
| Preceded2: | Juan A. Albors |
| Succeeded2: | Pedro Vázquez |
| Birth Date: | July 20, 1934 |
| Birth Place: | Santurce, Puerto Rico |
| Death Date: | January 29, 2021 (aged 86) |
| Death Place: | Syracuse, New York |
| Profession: | Politician |
| Party: | New Progressive Party |
Reinaldo Paniagua Diez (July 20, 1934 – January 29, 2021) was a Puerto Rican politician who was the seventh Puerto Rico Secretary of State from January 2, 1977, to 1979, under Governor Carlos Romero Barceló and served as acting Governor whenever the governor was traveling. He had previously been Romero-Barceló's campaign manager during the 1976 gubernatorial campaign. Reinaldo Paniagua Diez was owned the Caribbean winter baseball team, Santurce Cangrejeros from 1976 to 2002.
Paniagua was born on July 20, 1934,[1] to Rita Diez and Reinaldo Paniagua. He died on January 29, 2021, of natural causes.[2]