Linear A, also known as Proto-Linear, is the earliest of the Aegean linear scripts. For a time it was current at the same time as the hieroglyphic script, but appears only on clay tablets, not on seals. It is made up of ideograms to represent objects and numbers following a decimal system. Its texts are generally read from left to right, but occasionally from right to left. It has much in common with the hieroglyphic system, but does not in fact seem to derive from it as was initially thought.

The earliest linear writing was invented in Crete during the Neopalatial period (1600-1390 BC). Examples have been found in palace villas and archives. Its use continued until the destruction of the palaces in the Late Minoan IB period. The latest examples of Linear A come from the Late Minoan I period (1550-1450 BC) and do not occur in the strata of the Mycenaean occupation of Knossos. It seems that to have been the model for a particular Cypriot script from which Linear B, the earliest form of written Greek, may have derived.

The linguistic structure of Linear A differs considerably from the structure of the Greek of Linear B. Only a restricted number of examples of Linear A have been preserved in comparison with Linear B, most of which come from northern Crete. Most Linear A texts were found in the villa of Agia Triada, and recently a considerable number have been found in Chania. Its diffusion indicates that the use of Linear A in Crete was widespread. Examples have also been found further afield in Aegean, in Milos, Kea, Samothrace and Miletus, for example. Although few in number, the surviving examples of Linear A are sufficient to conclude that it represents the pre-Hellenic language of Minoan Crete.

Linear A texts have also been found on various ritual objects. Inscriptions on stone sacrificial tables have been found at Knossos, Archanes, Mallia, Phaistos and Zakros. Moreover, as an inscribed bronze flask from Kophinas indicates, Linear A was also used for votive inscriptions.