Hardware Trojans (HTs), maliciously inserted in an integrated circuit during untrusted design or fabrication process pose critical threat to the system security. With the ever increasing capabilities of an adversary to subvert the system during run-time, it is imperative to detect the manifested Trojans in order to reinforce the trust in hardware. In this regard, Machine Learning (ML) algorithms, with their intrinsic capability to execute feature engineering at high learning rates, are emerging as promising candidates to be utilized by system defenders. In this paper, we explore Trojan detection mechanisms that are based on ML, and thereby investigate the prowess of the ML algorithms in bolstering system security. Furthermore, we analyze the efficiency of each proposed Trojan detection strategy based on the underlying ML algorithm. Finally, we underline some problems with existing Trojan detection approaches and discuss future research in the interest of improved performance of the employed ML algorithms, thus aiding in enhancing the intended hardware security.