Acknowledging that Indigenous Peoples and local communities (IPLCs) hold vast knowledge about coastal-marine ecological systems which is often overlooked in marine/maritime spatial planning (MSP) initiatives, this publication aims to assist MSP practitioners in effectively involving IPLCs and including Indigenous and local knowledge (ILK) into MSP processes, while respecting universal human rights and internationally recognised ethical principles. It also seeks to foster co-management practices between governments and Indigenous Peoples and local communities in the development of MSP processes at the local level and to encourage MSP initiatives led by rights-holders inside their ancestral territories.The first section introduces the purposes and objectives of the publication. The second section presents essential international frameworks and ethical principles to be taken into consideration when engaging IPLCs and embracing ILK, including: the ILO Convention 169 on Indigenous and Tribal Peoples (1989); the United Nations Declaration on the Rights of Indigenous Peoples (2007); relevant FAO guidelines targeting small-scale fishers and Indigenous Peoples; the Paris Agreement of the United Nations Framework Convention on Climate Change (2015); protocols and frameworks related to the Convention on Biological Diversity; the Agreement under UNCLOS on the Conservation and Sustainable Use of Marine Biological Diversity of Areas beyond National Jurisdiction (2023); and the UNESCO/UNEP-WCMC Practical Guidelines on working with ILK in National Ecosystem Assessments (2023).