Haret (Romanian pronunciation: ['spiru ha'ret]; 15 February 1851 – 17 December 1912) was a Romanian mathematician, astronomer and politician.
He made a fundamental contribution to the n-body problem in celestial mechanics by proving that using a third degree approximation for the disturbing forces implies instability of the major axes of the orbits, and by introducing the concept of secular perturbations in relation to this.
As a politician, during his three terms as Minister of Education, Haret ran deep reforms, building the modern Romanian education system.
He was made a full member of the Romanian Academy in 1892.
He also founded the Astronomical observatory in Bucharest, appointing Nicolae Coculescu as its first director.