Since its first publication in 1971 of ISO/R 1996:1971 on Acoustics Assessment of Noise with Respect to Community Response, the International Organization for Standardization (ISO) has developed and published a range of standards for environmental noise assessment. The main ISO 1996 series of standards on Description, Measurement and Assessment of Environmental Noise has been developed in phases. Since then, a wide range of other standards have been added, covering different aspects such as attenuation of sound during propagation outdoors, quality assurance of software for the calculation of sound outdoors, soundscapes, and noise from shooting ranges, airports, and industrial plants. This chapter provides an overview of ISO standards related to environmental noise assessment. It also describes the historical development of the ISO 1996 series of standards. Current developments, including their status, are described. Excluded from this chapter are the ISO standards concerning noise at work, indoor noise assessment, and assessment of individual source emission and of noise barriers. However, a reference to all standards managed by ISO Technical Committee 43 Sub Committee 1 Acoustics – Noise is included in this chapter. Also excluded are other international standards such as ISEE blasting and national or regional standards as produced by BSI, DIN, AFNOR, etc. or in European Union-funded projects such as Harmonoise/Imagine and CNOSSOS-EU.