Efficiency is recognized as an indispensable factor in ensuring the stability and sustainability of political systems. Accordingly, governments derive legitimacy from their level of functional effectiveness. More precisely, as long as a political system maintains its image of efficiency, the likelihood of internal tensions and systemic collapse remains low. Conversely, dysfunction in the system’s performance leads to public alienation and deepens the divide between state and society. Given this, the functionality of political systems has been a central concern among scholars of political development. In this context, Gabriel Almond and Bingham Powell have proposed a distinctive theory regarding the functional capacities of political systems, identifying five core functions: extractive, regulative, distributive, symbolic, and responsive. Based on this framework, the present study seeks to answer the following question: To what extent was the Pahlavi regime able to fulfill the functional requirements of a political system in relation to its environment? The proposed hypothesis suggests that, due to the increasingly authoritarian nature of the Pahlavi regime, it failed to perform adequately across these five dimensions, ultimately leading to its collapse. The findings of the study indicate that the accumulation of ineffective policies played a decisive role in the regime’s downfall. This research has been conducted using a causal-analytical method and is based on data collected through library-based sources.