What is the equivalent of O-1 rank in the Marine Corps?

The equivalent of the O-1 rank in the Marine Corps is the Second Lieutenant. In the United States Armed Forces, officer ranks are generally classified by a system that assigns pay grades to different ranks. The O-1 pay grade corresponds specifically to the rank of Second Lieutenant in the Marine Corps.

Second Lieutenants typically serve as the first level of commissioned officers, often leading small units and making the transition from cadet to officer. This rank is fundamental for new officers as they begin their military careers, taking on leadership roles and gaining essential experience.

In contrast, the other ranks listed correspond to higher pay grades and levels of responsibility within the military. Lieutenant Junior Grade is an O-2 rank in the Navy and Coast Guard but does not apply to the Marine Corps in the same way, while Captain and Major are higher ranks—O-3 and O-4 respectively—indicating a greater level of experience and responsibility. This distinction is crucial for understanding the hierarchy within the Marine Corps and the structure of commissioned officer ranks.