There is great deal of controversy among the writers as to whether Alexander`s invasion made far-reaching effects or that India was not affected at all.

No widespread effects: Some writers are of the opinion that Alexander`s visit and attacks in India were in the nature of storm, which came and passed away without leaving any effects behind it. According to V. A. Smith, "The campaign of Alexander although carefully designed to secure a permanent conquest, was in actual effect no more than a brilliantly successful raid on a gigantic scale which left upon India no mark save the horrid-scars of bloody war. India remained unchanged." Smith further observes that after the year 316 B.C. No trace of the invasion remained.

Widespread and far-reaching effects of the invasion: Hemchandra Ray Chaudhari, Sri Jaichandra Vidyalankar, Dr. Majumdar, Dr. Ram Shanker Tripathi and certain other scholars, are of the view that Alexander`s invasion made widespread and far-reaching effects. E.R. Bevan remarks, "The European invasion of India was an event of too great magnitude not to have far-reaching consequences."

However, the truth lies mid-way between the two opposite views. To quote Paul Masson oursel, "The importance of this Indian campaign of Alexander has been exaggerated and underestimated. It is true that it had no decisive influence on the destinies of India, for its results were short lived. Yet the eight years of the Macedonian occupations opened an era of several centuries during which Hellenism was to be a factor not only of civilization but also of government on the western confines of the Indian world. Direct contact was established between the, Mediterranean civilization and those of the Punjab and of Central Asia, Semitic Babylonia and Persian empires was no longer a screen between west and east. These are facts of immense consequence, not only to Greek or Indian history but to the history of a world, which is only the real history."

In brief effects of Alexandra`s invasion can be discussed below:

Political effects
Help in the work of Chandra Gupta: Alexander`s invasion gave the lesson that small kingdom could not face the attacks of the foreigners. As remarked by Dr. R. K. Mookerji, "Alexander`s invasion promoted the political unification of the country. Smaller states that handicapped unity were now merged in the larger ones, such as those of Paurava, Abhisara, or Taxila. These conditions were favourable for the rise of an Indian empire to be shortly founded by Chandra Gupta."

Satrapy organization in northwest: Due to the establishment of Greeks in the northwest, satrapy system started in the field of administration.

Establishment of new cities: To commemorate his victories Alexander founded several cities, which remained long after his retreat.

Change in organization of Indian army: According to some writers Indians learnt much from the Greeks regarding the organization of army and adopted Greek system. However, Dr. V. A. Smith does not agree to this view, and writes, "Even to military, Indians showed no disposition to learn the lesson taught by the sharp swords of Alexander. The kings of hind preferred to go in the old way, trusting, to their elephants and chariots supported by enormous hosts of infantry. They never mastered the shock tactics of Alexander`s cavalry."

Effect on trade and commerce: It was the effect of the invasion of Alexander that new ways have opened for trade and commerce. And that too both through water and land. According to Dr. Smith the wall between east and west was broken with the opening of four ways. Out of which three through land and one through sea. According to Paul Masson Oursel, "Direct contact was established between the Mediterranean civilization and those of the Punjab and of central Asia, Semitic Babylonia and the Persian Empire were no longer a screen between the west and east." The opening of new ways gave a bonus to Indian trade and commerce and the consumption of Indian goods in foreign countries increased as well.

Historical advantages
The date of invasion of Alexander i.e. 327 B.C. has helped in the chronological reconstruction of the ancient history of India.

Cultural effects
The Greek influence in the field of astrology was very significant. Though the impact was not so permanent, still it brings some colour. The establishment of Greek empire in the northwest of India gave birth to the Gandhara. The style of sculpture was remarkable at that time. Indians learnt much in the field of coinage from the Greek and learnt to make beautiful and well-shaped coins as well.

Thus it can be seen that although the effects of the invasion were not permanent yet for some time they influenced Indians. After some time Indians forgot them and hence there is no mention of Greek invasion in Indian texts.