The thesis is focused on theoretical and practical analysis of legal relations in the area of interplay between private standards and patents included in standards. Though up-to-date studies analyzed standards as a general category, this study’s emphasis is made on private standards because they are more efficient and common comparing to governmental and de facto standards. This thesis is the first one to provide definitions of a standard essential patent (SEP), a private standard, an abuse of SEP, and classification that distinguishes between the types and forms of SEP abuse. In particular, patent ambush and patent hold-up are defined as types of SEP abuse while refusal to license a SEP, royalty stacking and injunctive relief for a SEP are the forms through which the abuse may be carried out. Competition law rules have proven to be the most efficient mechanism to counteract abuses of standard essential patents in private standards due to considerable investigative and enforcement resources that competition authorities have, and broad standing that allows to protect «outsiders» who suffer from SEP abuse but were not engaged in the standard setting process (e.g. consumers). To counteract SEP abuse in private standards, competition law can be complemented by other mechanisms of private law, particularly, general norms on abuse of rights from civil law, but also intellectual property and contract law in cases when patent owner who abuses a SEP does not possess market dominance. This thesis specifically focuses on the studies of SEP abuse in the works of foreign scholars, judicial practice in the EU, US, China and India and also international WTO agreements such as TRIPS and TBT Agreements. Asian experience is important because China became the first country to implement competition rules that counteract SEP abuse into national legislation. Having analyzed the experience of EU, USA, China and India, this thesis argues that application of an injunctive relief or refusal to license a SEP may result in SEP abuse and amount to violation of competition law if a willing licensee is present, which underlines the necessity to frame and implement the concept of a willing licensee into national legislation. The practice of EU, US, China and India should also be mutatis mutandis considered when determining the amount of a royalty rate on FRAND terms, which should constitute not a percentage from a value of a product but rather a range within which mutually acceptable royalty rate would be determined. As to WTO law, rules in TRIPS Agreement, such as exceptions from exclusive rights of a patent owner or provisions to control anti-competitive practices, could be used to counteract SEP abuse. The obstacle may be that these rules require their implementation into domestic law. TBT Agreement does not cover interaction between patents and private standards while there is a demand to discipline this area. The results of the study have been reflected in the proposals to reform national Ukrainian legislation to facilitate counteraction of SEP abuse, taking into consideration international experience.