Since its foundation, the Islamic Republic of Iran has developed its relationship with non-state allies throughout the Middle East and beyond, often using them to engage in proxy warfare with its enemies. This topic has seen increasing attention by academics and policy-makers. Using the proxy groups as case studies and classical comparison, this thesis analyzes what drives Iran to deploy these proxies to wage war on its enemies, and under which circumstances Iran does not engage in proxy warfare, as well as the factors that make Iran develop lasting and deep relationships with its proxies and under which circumstances these relationships stay superficial. Three main hypotheses are tested: first the identity-based hypothesis, that Iran feels compelled to help fellow Shias and the Palestinians in their struggles against local oppressors, the West and Israel, being driven by a responsibility to protect them born out of Shia religion and Khomeinist revolutionary ideology, together forming the Axis of resistance. Second the power-based hypothesis, that Iran is primarily driven by realist concerns to defend and secure itself and its sphere of influence, making proxies Iran’s pawns. Lastly a factionalism-based hypothesis, an alternative explanation is competition between the Islamic Revolutionary Guards Corps and the Foreign Ministry as causing the IRGC to engage with proxies to pursue their foreign policy. By testing these three hypotheses in several case studies spanning four decades and geographically the Middle East and beyond, this thesis presents a comprehensive approach to the reasons behind Iranian proxy warfare as well as a contribution to a more identity and ideology focused approach to the study of proxy wars.