Well-performing health systems are critical for pursuing universal health coverage and for achieving health-related SDGs. It is important to grasp key concepts such as systems approach, analysis, and thinking before taking a deeper dive into health systems. Health systems can be described in broad or restricted terms. The most widely accepted definition includes all the institutions, actors, and activities whose primary purpose is to promote, restore or maintain health. There are many health system frameworks and models of which four have been reviewed - WHO’s Health System Conceptual Framework, Control Knobs Framework, Kielmann’s and Roemer’s Health System Models. No single framework addresses all aspects of a health system. It is more useful to know the strengths and limitations, and usefulness of each in achieving a specific objective such as for description and analysis, designing system reform, or evaluation. Interventions whether system-led, programmatic or those addressing health determinants are part of the wider health system and offer the best opportunity for improving health outcomes when addressed together.