This chapter emphasized the pivotal role of GIS in environmental decision-making by exploring spatial data collection methods, including GPS, remote sensing, LiDAR, and drones, highlighting their contributions to understanding environmental attributes. Spatial data integration and management within GIS are discussed as an efficient approach to data storage, retrieval, analysis, and modeling that facilitates evidence-based decision-making. Public engagement and communication using GIS can foster stakeholder involvement. GIS's relevance in shaping environmental policies and regulations is emphasized, covering habitat preservation, water resource management, air quality regulation, and more. It also discussed the concept of SDI and its role in addressing environmental challenges. The challenges and future directions of GIS in environmental planning and management are addressed, covering data quality, privacy, capacity building, and public engagement. Future prospects include AI, real-time data integration, cloud-based GIS, 3D and virtual reality, and crowdsourcing are also endorsed.