This improved sealed envelope assembly with locking pockets for free insert material comprises an envelope with front and back plies and at least one insert ply therebetween. The envelope has internal securing means such as adhesive lines adjacent the peripheral edges of the front and back plies for uniting the same, the securing means being spaced from the periphery of the insert ply so that the insert ply lies wholly within the enclosure bounded by the securing means. The back ply has a plurality of spaced embossments located inwardly of the securing means and adjacent the periphery of the insert ply, preferably on at least two sides, each of the embossments comprising a tab having a base portion preferably integrally secured to the back ply along a substantially straight deflection line and a free portion deflected towards the front ply in substantial overlapping relationship with the insert ply so as to form, in conjunction with the back ply, a locking pocket for the insert ply. Lines of weakening in the front and back plies are located along one side inwardly of the deflection lines whereby separation of the plies along the lines of weakening removes a marginal portion of the plies, opens said envelope assembly and frees the insert ply from the locking pockets so that it can be readily removed.