Technological Pedagogical Content Knowledge (TPACK) is a theoretical framework that has enjoyed widespread applications as it applies to the integration of technology in the teaching and learning process. This paper reviews the background for TPACK, discusses some of its limitations, and reviews and introduces a new theoretical framework, 21st Century Pedagogical Content Knowledge (21st Century PCK), to clarify the discourse surrounding teaching and learning in an increasingly technological world with specific applications to science teaching and learning.