Faithful to meet Longford in decider on Saturday.
Offaly will face Longford in the O'Byrne Cup final on Saturday next after the Faithful County beat Westmeath by 16 points to 11 at Bord na Mona O'Connor Park in Tullamore on Saturday.
A strong second half saw John Maughan's men pull away from the Lake County.
Elsewhere Galway and Roscommon will contest the Connacht FBD league final next Saturday at Dr Hyde Park
In new manager Pádraic Joyce's first game in charge the Tribesmen beat Mayo 3-2 on penalties in Castlebar after playing out a 1-17 draw.
Roscommon then stormed into the decider - beating Leitrim 7-16 to 7 points in the other last-four tie.
In Ulster, reigning champions Tyrone beat Down 2-16 to 1-10 in the semi-finals of the Dr McKenna Cup and they'll face Monaghan in the final.
In hurling's Walsh Cup semi-finals - Galway beat Dublin 19 points to 18 in Parnell Park in new manager Shane O'Neill's first game in charge of the Westerners.