This thesis examines the bases for the implication of terms, the relation between interpretation and implication as well as the relation between the bases for the implication of terms and the theories of contract formation. There is authoriative support in England and South Africa for the following bases for the implication of terms: (a) unexpressed subjective consensus; (b) the reasonable expectation principle; (c) logic and/or the rational construction of the contract; (d) legal rules or incidents governing particular kinds of contractual relationships; and (e) the <i>Moorcock</i> doctrine. It is submitted the the <i>Moorcock</i> doctrine should be discarded, because it involves an artificial approach to the resolution of cntractual disputes which obscures the true reasons for the implication of terms in individual cases and is conducive to much uncertainty. The law will be none the poorer if the doctrine is abandoned, because the courts' powers to interpret contracts and to recognise novel legal rules governing particular kinds of contractual relationships are adequate tools for the resolution of contractual disputes. It is shown that the courts frquently manipulate the principles of the <i>Moorcock</i> doctrine in the interest of justice. This practice has obscured the emergence of a principle to counter-balance the doctrine of sanctity of contract. It is argued that the appropriate counter-balancing principle is that the courts have the power to adopt and apply rules governing particular kinds of contractual relationships after an evaluation of the competing considerations of policy attending the kind of relationship in question. Examples of specific policy considerations which may be of assistance in this regard are supplied. The influence of English law on the South African law relating to implied terms is examined.