The determination of the meaning of colonization and of the factors that generated it, constitutes until today an issue of constant dispute in the academic world. Scholars are unable to agree as to the causes of the colonial movement.

A large portion of scholars focuses on the problem of overpopulation. Several years now it is maintained that during the 8th and 7th century BC, there had been a dramatic population increase in the Greek mainland. In order to defuse the tension from that problem, groups of citizens were sent to found colonies in regions, mainly outside Greece. Over the last years however, particular emphasis has been given to economic factors. Certain scholars maintain that the main reason for the spread of colonies was the acquisition of cultivable land. Others, on the other hand, talk about the importance of metals in the Archaic period and consider that their quest was the main reason that caused the colonial wave.

In any case, the prevalent opinion is based on both of the above theories and accepts that colonists were impelled by the need to find cultivable land, as well as regions abundant in metals, which the Greek subsoil did not have (Strabo, Geographia 6.2.2).
Lastly, a group of scholars pinpoints the outset of the colonial movement also in natural disasters, such as the frequent droughts of that period that led to bad crop. They maintain that colonization remedied not only the problem of overpopulation, but mainly it healed the wounds caused by these incessant disasters.
But apart from causes of social or economic nature, as well as adverse environmental conditions, certain cases of colonization have been interpreted mainly as the result of political pressures.

In the Greek mainland, inevitable difficulties in agricultural cultivation probably favoured thoughts concerning trade. However, it seems unlikely that colonies were founded for commercial reasons, especially since the colonists were sent in search of new cultivable lands and pastures.

Usually trade in its wider sense, was the result and not the cause of the colonial movement. Trade, seen as a motive, was never the primary reason for the establishment of communities or colonies, neither in Asia Minor nor in the West. But in general, the success of the colonial movement was due to some extent to the simultaneous development of trade. Greek colonists inhabited regions with climatic conditions similar to those of Greece. This choice allowed them to adjust easier, but also to adapt with ease their agricultural techniques to their new homes.

The foundation of colonies provided significant overseas markets and safe harbours for maritime enterprises. But above all, it reflected the general evolution brought about in the Aegean region during the Archaic period. The creation of the polis, the use of coinage and the accession of tyrants have been considered by many as motives, but also as consequences of the whole activity.