During Middle ages, Haro grew up, absorbing the villages in the vicinity to Haro, like Tondon and Bilibio. In 1187, Alfonso VII of Castilla bestowed privileges, and Alfonso X "the Wiseman" confirmed it , this privileges included political, administrative, criminal and economical regimens which controlled the village. In the Late Middle Ages (1358) took place a junta to regulate an association with the aim to protect themselves from the disorders originated during that time.

In XIV and XV century, the village fell into Trastamara hands, till 1430, when Juan II of Castilla donated to Don Pedro Fernandez de Velasco, as a reward for his support in the wrestle against Juan II of Aragon. In 1627 the first printing press arrived in Haro, being the first published work, and being his printer Juan de Mongaston in 1631..