This book constitutes the refereed proceedings of the 44th National Conference of Theoretical Computer Science, NCTCS 2026, held in Jinhua, China, during August 23–25, 2026.

The 8 full papers included in these volumes were carefully reviewed and selected from 62 submissions. The are organized into the following topical sections: Logic, Software Theory, and Programming Theory; Algorithm Theory and Data Structures; Data Science Theory and Algorithms; and Computational Complexity.