In November 2010, the International Standardization Organization (ISO) published the ‘International Guidance Standard on Social Responsibility - ISO 26000’ (ISO 26000). ISO 26000 is a voluntary international standard that provides guidance to companies and other organizations on social responsibility (SR) and sustainable development (SD). The guide provides a common understanding of SR, through agreed terms and terminology. SR is defined as the: responsibility of an organization for the impacts of its decisions and activities on society and the environment, through transparent and ethical behaviour that - contributes to sustainable development, including health and the welfare of society; - takes into account the expectations of stakeholders; - is in compliance with applicable law and consistent with international norms of behaviour; and - is integrated throughout the organization and practised in its relationships. ISO 26000 recognizes human rights as a core component of SR and identifies various human rights issues that business enterprises should consider in discharging this responsibility, inter alia, due diligence, human rights risk situations, and resolving grievances. According to Henriques, ISO 26000 is a ‘powerful statement of the moral and practical issues facing companies and organizations’ that can become influential and make valuable contributions to the realization of human rights, especially in developing countries. ‘Outside the West, where many companies are feted with numerous standards, initiatives and the lure of “corporate social responsibility”, ISO 26000 will be influential. It will be the main port for call for many companies in the South seeking to address their wider responsibilities, perhaps for the first time’. It should be underlined that ISO’s involvement in the project of ISO 26000 was disputed from the start. ISO is an international non-governmental organization whose membership base consists of National Standards Bodies (NSBs). ISO’s main activity has been the development of technical standards for products and processes to facilitate trade. ISO remains a ‘de facto monopoly’ in most domains of international technical standards permitting product interoperability. ISO went outside its comfort zone by entering the field of SR a public interest issue and developing a type of international standard that differs in various aspects from its predecessors, including the ISO 9000 – Quality Management System Standards (MSSs) and ISO 14000 – Environmental MSSs. ISO’s involvement in the field of SR, and furthering the SD agenda, was conditional upon ISO revising its modus operandi. To this end, carefully crafted procedures to ensure an equitable and balanced representation of traditional and non-traditional stakeholders and North-South interests, were put in place. The consultation of non-traditional stakeholder voices also resulted in ISO deciding that the future deliverable would be a voluntary ‘guidance document’, explicitly ‘not intended or appropriate for certification purposes or regulatory or contractual use’. The particular nature of ISO 26000 has triggered discussion among practitioners and academics alike. Scholars have taken a particular interest in the legitimacy and effectiveness of ISO 26000’s multi-stakeholder development process. This process involved 400 experts and 200 observers from 99 countries and 42 international organizations. Scholars have pondered the added value of ISO 26000 in the already crowded field of CSR in which other initiatives provide substantive guidance on SR, ISO 26000’s dissemination, potential and actual impact on the behavior of companies and on the overall development agenda. Less attention has been paid to the potential and actual effectiveness of ISO 26000 in relation to human rights. This chapter examines the effectiveness of ISO 26000 for human rights, 10 years after its publication. The effectiveness of ISO 26000 can be defined in various ways. Of particular relevance for the purpose of this chapter is how well ISO 26000 serves the goal it has set for itself and the achievements in relation to human rights, within the overarching objective of SD. Moreover, it discusses the relevance and suitability of ISO 26000 in contributing to resolving key challenges in the business and human rights domain. Hence, the manner in which ISO 26000 defines human rights responsibilities, its dissemination globally and the actual impact on business standards and practices will be important aspects to consider when determining its effectiveness. The first section of this chapter describes the origins and development of ISO 26000, and how it aims to contribute to human rights. The second section conducts a literature review of academic writing on ISO 26000, focusing on the effectiveness of ISO 26000, including in relation to human rights. The third section exposes current debates, emphasizing the linkage between ISO 26000 and the United Nations Guiding Principles on Business and Human Rights (UNGPs) , and identifies outstanding issues. The UNGP have been widely accepted as the framework to address the adverse human rights impacts of business enterprises. The final section provides an agenda for future research. This chapter concludes that, for a number of reasons outlined below, ISO 26000 has not been effective in leveraging business practices. ISO 26000 does not fully reflect the UNGPs and this undermines its effectiveness as a tool and its potential transformative effects on fostering respect for human rights within companies, as part of a broader solution to promote human rights protection against business related harms. Moreover, ISO 26000 risks losing its relevance compared to other initiatives setting international SR standards, mainly because it has not been updated since its publication in 2010. Whilst a revision should give it a new impetus, one should question whether efforts are better spent elsewhere, on initiatives and processes of business and human rights governance that bring actual change in the lives of people.