Since the departure of the field of International Business (IB) from international economics orientation various theoretical perspectives of IB was built by taking into account other business related disciplines. In this article, we have concentrated on main theories of FDI and MNCs, namely, market imperfection and oligopolistic reaction theories, product cycle theory (PCT), internalization theory (IT), eclectic (OLI) theory, incremental (Uppsala) theory (UT), and network theory (NT). Not only we have presented origins and main arguments of these theories but also we have, to some extend, evaluated the strengths and weaknesses of them.

Since the departure of the field of International Business (IB) from international economics orientation various theoretical perspectives of IB was built by taking into account other business related disciplines. In this article, we have concentrated on main theories of FDI and MNCs, namely, market imperfection and oligopolistic reaction theories, product cycle theory (PCT), internalization theory (IT), eclectic (OLI) theory, incremental (Uppsala) theory (UT), and network theory (NT). Not only we have presented origins and main arguments of these theories but also we have, to some extend, evaluated the strengths and weaknesses of them.