The secondary interaction contribution in complexation via multiple hydrogen bonds was estimated using model complexes. Based on the results of hydrogen fluoride complexes, proton donor (D) - proton acceptor (A) type secondary interaction was attractive, and the total stabilization energy should be increased about 25-35%, based on hydrogen bond interaction, by the D-A type secondary interaction. The D-D type secondary interaction was very small. The A-A type secondary interaction was repulsive, and the total stabilization energy should be decreased about 10-20% based on hydrogen bond interaction, by the A-A type secondary interaction.