When language service providers (LSPs) court new clients, three letters can have a big impact on their success: ISO. The Geneva, Switzerland-headquartered International Organization for Standardization, or ISO, has developed over 20,000 standards for a range of industries. There are, at present, 16 published standards under the direct responsibility of the Translation, Interpreting and Related Technology Technical Committee, including a new standard for legal interpreting introduced in April 2019. And certification bodies perform independent audits to confirm that businesses are operating in accordance with ISO standards. Slator’s 2020 Pro Guide on ISO and Quality Management for Language Service Providers examines the certification patterns of 140 LSPs in Slator’s Language Service Provider Index (LSPI). Of the LSPs surveyed, nearly three-quarters have at least one ISO certification; 54% have more than one. The analysis found that LSPs’ most common ISO certifications are both industry-specific (e.g., translation services, post-editing of machine translation) and more general (quality management systems, information security systems). ISO 9001:2015, for quality management systems, is the most widely held certification among LSPI companies, with 67% certified against this standard. Yet, 40% of Boutique LSPs lack certification against this essential standard. One unexpectedly popular certification relates to quality management systems for medical devices, which generate substantial demand for translation. This squares with Slator’s April 2020 coverage of medtech company Hamilton Bonaduz AG, recently tasked with automating Covid-19 testing; whose technical content manager said that both translation quality certifications and those specific to medical and laboratory equipment help ensure that translations comply with regulatory demands. Clearly, for many clients, ISO certification is a prerequisite as it signals expertise. For others, it demonstrates an LSP’s commitment to quality that convinces a buyer to choose one LSP over another. In fact, certain ISO standards are designed to improve linguistic quality and enhance customer satisfaction. Although ISO certification does require an investment of time and resources, many LSPs find that it pays off. Research from Harvard Business School has shown that companies certified against ISO 9001 grow faster in terms of sales, employment, and payroll compared to companies without the certification, with smaller businesses gaining the most. Similarly, implementing ISO standards has been consistently shown to have a positive impact on operational efficiency, and may even protect LSPs from fallout due to business disruptions — an especially relevant consideration in today’s uncertain market.