The literature on the causes of health care reform is dominated by institutionalist accounts, and political institutions are among the most prominent factors cited to explain why change takes place. However, institutionalist accounts have difficulty explaining both the timing and the content of reforms. By applying a range of explanatory approaches to a case study of health reform in New Zealand since the 1970s, this article explores some of the theories of reform beyond institutionalism, particularly those that take into account problem pressure, policy ideas, and the more agency-centered factor of partisan ideology. The aim is not to dismiss institutionalism but to try to fill some of the gaps that cannot be addressed with institutionalist theories alone. The detailed analysis shows that various factors played a role in conjunction, namely, problem pressure, policy ideas, and the ideology of parties in government. Partisan ideology, in particular, has perhaps been prematurely ignored by health care scholars.