The First Bench, comprising Chief Justice M Y Eqbal and Justice T S Sivagnanam, said the system, introduced by the previous DMK government, should be implemented in all classes.
Since the textbooks had already been printed, the government could set up a group to delete or correct any portions within three months, the bench said in its order.
The Court also quashed the amendment to the Tamil Nadu Uniform System of Education Act which sought to defer the implementation of the scheme.
Observing that deferring the Samacheer system was one of the decisions taken at the first Cabinet meeting of the Jayalalithaa government soon after assuming office in April, the bench said it was "arbitrary" and taken in too short a time.
Tamil Nadu government had earlier contended that the amendment to the Tamil Nadu Uniform System of Education Act seeking to defer implementation of the scheme was to properly implement the uniform system of education.