A polyolefin-based composition showing improved weldability using high frequency(HF) includes (1) a base polymer selected from (a) a homogeneously branched, linear or substantially linear ethylene/alpha-olefin copolymer; (b) a homogeneously branched propylene/alpha-olefin copolymer; or (c) a combination thereof; and (2) at least one secondary component selected from (a) an ethylene vinyl acetate copolymer having from 5 to 40 wt% vinyl acetate; (b) an ethylene-ethyl acrylate having from 5 to 25 wt% ethyl acrylate; and (c) a combination thereof. The combination of the specified polyolefin with the specified secondary component, which is a polar polymer, makes these formulations HF weldable, with a cohesive welding failure, a weld strength for 10 mil thick film greater than 7 lb/in (1.23 N/mm) at a weld time of less than or equal to 6 seconds. The formulations may also exhibit good calendering processability and mechanical properties.