Synthetic fibers with non-circular cross-sections are used in air filters. These fibers may offer performance advantages over traditional fibers with circular cross sections because they have more surface per unit volume of fiber upon which particles can collect. Starting with a solution for the velocity field around fibers with elliptical cross-sections, expressions for predicting the single-fiber efficiency for particle collection by the interception mechanism were developed for elliptical fibers. The interception efficiency predictions depend on filter solidity, fiber properties such as size, aspect ratio, and orientation of the cross section relative to the incoming flow, and particle diameter. The expressions demonstrate that single fiber interception efficiency for elliptical fibers generally increases with increasing particle diameter, increasing solidity, increasing aspect ratio, and as the major axis of the ellipse becomes more perpendicular to the incoming air flow.