The 13 children of FDNY firefighters killed on 9/11 are set to graduate from the Fire Academy Tuesday, appearing in their handsome dress blues for the first time in a Post photo exclusive.

The probationary smoke eaters — a dozen men and one woman — are among 301 who will proudly graduate as FDNY’s Class of 2019 in what will surely be an emotional ceremony in Brooklyn.

This class includes siblings — two sons of one fallen firefighter, and the son and daughter of another hero.

It also has the most “legacy” members since 9/11, including the son of an NYPD officer killed in the terror attacks and the sons of two firefighters who died due to illness linked to rescue work at Ground Zero.