Rafaela Ybarra Arambarri de Vilallonga (16 January 1843 – 23 February 1900) was a Spanish Roman Catholic widow and the founder of the Sisters of the Holy Guardian Angels.

Rafaela Ybarra Arambarri de Vilallonga was born in Bilbao on 16 January 1843 to affluent parents part of the upper-class.

Bilbao experienced a rapid industrialization process and she set up a series of homes for working-class children and teenage girls as well as workshops for their proper training.

The premature death of her sister Maria de Rosario prompted her to raise and take care of her half-orphaned nephews which included the Basque linguist Julio Urquijo Ibarra.

On 8 December 1894 - alongside three others - made a solemn pledge to become a mother and educator to all poor children in Bilbao.

Theologians approved Ybarra's spiritual writings on 12 May 1937; the formal introduction to the cause came on 11 July 1952 under Pope Pius XII and she became titled as a Servant of God.

Pope Paul VI named Vilallonga as Venerable on 16 March 1970 after he confirmed that the late widow had led a model Christian life of heroic virtue.