Kazakhstan's legal framework concerning oil spill issues has been reviewed and updated during 2015–2019, driven by the adoption of good international practice. Ensuring the full response toolkit is available and options are chosen to mitigate the overall impact of an incident were critical principles. The Oil Spill Preparedness Regional Initiative (OSPRI), in conjunction with national industry (North Caspian Operating Company - NCOC and KazMunaiGaz - KMG), shared the net Environmental Benefit Analysis (NEBA) approach and later the Spill Impact Mitigation Assessment (SIMA) with key agencies and authorities as part of this effort. As the first step, workshops and seminars on NEBA were organized at local and national levels. These were facilitated by international experts and national consultants to build awareness and understanding. The second step was to embed NEBA within the legal framework. The legal system has a strong hierarchy including Codes, Laws and Orders. The National Contingency Plan (2015), approved by Order, acknowledged NEBA and gave impetus to develop additional legislation on the NEBA process. To ensure proper legal force, it was suggested to embed NEBA higher up the hierarchy, in the Subsoil Use Code (2017). Practical implementation of NEBA (during simulation exercises) and review by authorities of a draft NEBA report prepared by NCOC, revealed that the process required further clarification. It was not clear how NEBA should be presented in contingency plans, for authorities' review and approval i.e. whether it should be a separate report or incorporated within the plan. It was mooted that proposed amendments to the Environmental Code would aid clarification. In order to support a coherent process of contingency plans' approval, NEBA should be supported by a suitable and recognized implementation methodology. The SIMA methodology has been proposed as an option in Kazakhstan. Work on the Environmental Code's amendments, incorporating suitable clarifications, is expected to be completed in 2020. Based on the experience of NEBA adoption in Kazakhstan, cooperation between industry and authorities, exercises and workshops leads to positive results. The process has taken some years, as capacity building and legislative developments were required, but is reaching a successful conclusion. This will inform the choice of response options for any future incidents, to achieve least overall ecological and socio-economic impacts.