As cornerstones for biodiversity conservation, protected areas (PAs) are critical to safeguard biodiversity. However, PAs are criticized for their limited ecological effectiveness and their negative social impacts. This article seeks to provide an overview on the contested nature of PAs and places PAs in the tension field of conservation and development, which are diverging forces specifically in the Global South. A reconciliation of PAs as parts of a wider landscape of interlinked social-ecological systems may increase the potential of PAs to contribute to the sustainable development goals, including the creation of sustainable human-nature relationships, environmental health and landscape resilience. The environmental justice framework appears useful in the endeavour to improve the social-ecological integrity of current conservation practises and to increase the ability of PA systems to withstand shocks. Considering PAs as systems in which people and nature interact in manifold ways may help increase their integrity, but understanding these interactions requires sustainability researchers and conservation practitioners to recognize the diversity in value towards nature, nature understanding and conceptualisations. Such deep understanding seems pivotal in working towards synergies of sustainable use, biocultural diversity and wilderness. Concludingly, this article emphasizes the need for holistic approaches rather than in sectoral specialisations and radicalisations to achieve arrays of sustainability goals.