The paper discusses some important biotic interactions with typical examples from walnut orchard ecosystem of Kashmir valley. The ones that have been discussed are competition, predation, herbivory and symbiosis. Two walnut aphids viz. Chromaphis juglandicola and Panaphis juglandis are primary herbivores, sucking the phloem sap, of walnut orchards in Kashmir valley. These aphids show mutualistic relationship with ants. Also, these aphids are preyed upon by Lacewings and Ladybird beetles. An aphidiid, Trioxys pallidus parasitizes C. juglandicola and is its primary parasitoid. These species interactions can be used as a framework for studying walnut orchard ecosystem properties and may aid in predicting impact of anthropogenic interferences on the same.