It would seem axiomatic that the law should be coherent in the sense that it should be consistent and correspond to an underlying justificatory rationale. Indeed, coherence would appear to be a good, in and of itself, and give rise to other benefits which are desirable in a legal system. In this article, I explore the value and achievability of coherence. I argue that it is largely inevitable that common law legal systems are not coherent, but that each legal system will comprise areas of coherence. I examine whether it is possible to improve coherence through legislation or adjudication but conclude that any coherence attained through the former may be temporary and achieving coherence through the latter is difficult both in principle and in practice. In looking at the value of coherence, I contend that while coherence may have various intrinsic and instrumental benefits, its value should not be overstated; many of the benefits which coherence is said to provide are present in legal systems where it is lacking; other benefits depend on the awareness of a country’s citizens and I suggest that, outside of extremes, citizens are probably unaware of the degree to which their legal system is coherent. Moreover, full coherence may lead to characteristics which are undesirable in a legal system.