A health system, also sometimes referred to as health care system or healthcare system is the organization of people, institutions, and resources to deliver health care services to meet the health needs of target populations.

There is a wide variety of health systems around the world, with as many histories and organizational structures as there are nations. In some countries, health system planning is distributed among market participants. In others, there is a concerted effort among governments, trade unions, charities, religious, or other co-ordinated bodies to deliver planned health care services targeted to the populations they serve. However, health care planning has been described as often evolutionary rather than revolutionary.

The goals for health systems, according to the World Health Organization, are good health, responsiveness to the expectations of the population, and fair financial contribution. Progress towards them depends on how systems carry out four vital functions: provision of health care services, resource generation, financing, and stewardship. Other dimensions for the evaluation of health systems include quality, efficiency, acceptability, and equity. They have also been described in the United States as "the five C's": Cost, Coverage, Consistency, Complexity, and Chronic Illness. Also, continuity of health care is a major goal.

Health care (or healthcare) is the diagnosis, treatment, and prevention of disease, illness, injury, and other physical and mental impairments in humans. Health care is delivered by practitioners in medicine, chiropractic, dentistry, nursing, pharmacy, allied health, and other care providers. It refers to the work done in providing primary care, secondary care and tertiary care, as well as in public health.

Access to health care varies across countries, groups and individuals, largely influenced by social and economic conditions as well as the health policies in place. Countries and jurisdictions have different policies and plans in relation to the personal and population-based health care goals within their societies. Health care systems are organizations established to meet the health needs of target populations. Their exact configuration varies from country to country. In some countries and jurisdictions, health care planning is distributed among market participants, whereas in others planning is made more centrally among governments or other coordinating bodies. In all cases, according to the World Health Organization (WHO), a well-functioning health care system requires a robust financing mechanism; a well-trained and adequately-paid workforce; reliable information on which to base decisions and policies; and well maintained facilities and logistics to deliver quality medicines and technologies.

Rebecca Onie (born 1977) is co-founder and Chief Executive Officer of Health Leads.

In 1996, during her sophomore year at Harvard College, Rebecca Onie founded Health Leads (formerly Project HEALTH) with Dr. Barry Zuckerman, Chair of Pediatrics at Boston Medical Center. As Executive Director of Health Leads, Rebecca oversaw the organization's growth to Providence and New York City.

After attending Harvard Law School, where she served as an editor of the Harvard Law Review and research assistant for Professors Laurence Tribe and Lani Guinier, Rebecca clerked for the Honorable Diane P. Wood of the U.S. Court of Appeals for the Seventh Circuit. She was also an associate at Miner, Barnhill & Galland P.C., a boutique law firm in Chicago, where she represented civil rights plaintiffs, health centers, affordable housing developers, and nonprofits.

During this time, Rebecca served as founding Co-Chair of Health Leads' Board of Directors. She returned to Health Leads as CEO in February 2006.

In 2009, she was honored to receive a MacArthur Fellowship, for “individuals who have shown extraordinary originality and dedication in their creative pursuits and a marked capacity for self-direction.” Most recently, O! Magazine named her to its 2010 Power List of twenty women who are “changing the world for the better.”