Unwritten law is simply that portion of Malaysian law which is not being enacted by Parliament or the State Assemblies and which is not found in the written Federal and State Constitutions. This category of law comes from cases decided by the Courts and the local customs, which is otherwise known as common law. The unwritten law mainly comprised of the English law, judicial decisions and custom law.

English law forms part of the laws in Malaysia. English Law can be divided into two which are the English Commercial Law and English Land Law. In section 5(1) of the Civil Law Act 1956 provides that The English Commercial Law is applicable in Peninsular Malaysia except Penang and Malacca as it stood on 7 April 1956 in the absence of local legislation. On the other hand, Section 5(2) of the same act, applies in Penang, Malacca, Sabah and Sarawak as the law administered in these states will be the same as law administered in England, in the like case at corresponding period. As for the English Land Law, none of the English Land Law concerning the tenure, conveyance, assurance of or succession to any immovable property or any estate, right or interest therein applies in Malaysia. In Malaysia, National Land Code is the law that governs the land matters. There is no any allowance for English land law, except in so far the National Land Code might expressly provide.

Approaching the judicial decision, judges do not decide arbitrarily. Instead, they are bound to follow certain accepted principles known as precedents. The system of binding judicial precedent is called stare decisis. It is created by the English judges and introduced into Malaysia upon colonization. Customs of the local inhabitants in Malaysia are also a source of law. Every race has its own customs. Hindu and Chinese customary law applied to the Hindus and Chinese respectively. Besides that, natives in Sabah