Most poultry farming that has been conducted by smallholders in Thailand are free-range and housing systems, which have risks of parasitic infection from the environment, particularly from tapeworms in the genus Raillietina and trematodes in the family Echinostomatidae. These have become important health problems in the poultry industry, causing low feed conversion ratios and leading to the loss of economic value. Our objective was to develop and validate a molecular technique based on duplex loop-mediated isothermal amplification (LAMP) together with lateral flow dipstick (LFD) assay for discriminating the infections between the genus Raillietina (R. echinobothrida, R. tetragona, and R. cesticillus) and the family Echinostomatidae (E. miyagawai, E. mekongi, E. macrorchis, and H. conoideum) in a single reaction. The developed assay was highly specific without cross-amplification with other poultry helminths and their hosts, at the optimized condition of 66 °C for 80 min. In addition, the results could be clearly visualized with the naked eye via LFD after incubating with probes at 66 °C for 10 min. The detection limit or analytical sensitivity of the Raillietina and Echinostomatidae groups were found to be 5 × 10