Petty officer, 2nd class, (PO 2), is a Naval non-commissioned member rank of the Canadian Forces.

Its Army and Air Force equivalent is sergeant (Sgt); together, Sgts and PO 2s make up the cadre of senior non-commissioned officers.

The full appellation Petty Officer 2nd Class or PO 2 in speech is generally used only when the second-class distinction must be made, such as to distinguish between members with similar names but differing ranks, or on promotion parades.

It is common practice to refer to the petty officer by this shorthand in all but the most formal correspondence (such as printing and inscription on awards).

Among enlisted sailors, 12 consecutive years of good conduct (categorized as no court-martial convictions and no non-judicial punishments) entitles the sailor to wear a good conduct variation of their rate insignia: the chevrons which are normally red are replaced with gold.

However, this may be waived in the event the sailor holds a critical rate, Navy Enlisted Classification or security clearance.

All U.S. Coast Guard petty officers wear red chevrons and red service stripes, until the rate of chief petty officer, where both chevrons and service stripes are gold.

In the US Navy, all petty officers wear red stripes and chevrons until they reach 12 consecutive years of service with good conduct (as determined by eligibility for the Navy Good Conduct Medal as its criteria).