Georg Michael Pachtler (14 September 1825, at Mergentheim, Württemberg – 12 August 1889, at Exaten, Netherlands) was a German Jesuit and educational writer.
His educational labours were interrupted twice, when he acted as military chaplain to the Tyrolese troops during the Italian campaign (1866), and to German volunteers in the papal army (1869–70).
After the expulsion of the Society of Jesus from the German Empire (1872), Pachtler lived mostly in the Netherlands and Austria, devoting himself to literary work.
Pachtler's volumes form the standard work on the educational system of the Jesuits; it is entitled: Ratio Studiorum et Institutiones Scholasticae Societatis Jesu, per Germaniam olim Vigentes.
The work contains the official documents of the society which have reference to education, parts of the constitutions, decrees of the legislative assemblies of the order, ordinances of generals, reports of official visitations, the various revisions of the Ratio Studiorum, schedules of study, disciplinary regulations, directions for the training of teachers, and treatises of private individuals which explain the practical working of the system.