Hernando Siles Reyes (5 August 1882 – 23 November 1942) was a Bolivian politician who served as the 31st president of Bolivia from 1926 to 1930.

Soon, he came to be regarded as one of the most charismatic Bolivian politicians in recent memory, especially when he broke openly with the domineering ex-President Bautista Saavedra, and exiled him along with his brother (hitherto Siles's own Vice-President).

Many more opponents were exiled, giving Siles some breathing room, but matters reached a breaking point when, in 1930, the President attempted to unilaterally increase his term in office, ostensibly to deal with the mounting economic and international crisis.

The latter was overthrown by General Carlos Blanco, who in 1931 called elections which were won by Daniel Salamanca of the Partido Republicano-Genuino.

His younger son Luis Adolfo Siles Salinas was acting President of Bolivia for a few months in 1969.