This thesis demonstrates achieving a net-zero energy commercial building in the hot, arid region of Saudi Arabia. The development process uses three main concepts: evaluating and assessing selected existing commercial buildings, incorporating energy efficiency strategies, and implementing renewable energy source technologies. This study has been divided into five chapters: Introduction and Problem Statement, The Net-Zero Approach, Background of Saudi Arabia and Its Climatic Variations, Case Studies, and Project Development and Demonstration. Initially, an assessment of the Umm Al-Qura University administration building was conducted in two steps: 1) collecting building data and creating a building simulation in eQUEST software to obtain accurate performance prediction results and 2) implementing energy efficient strategies for both passive and active systems to mitigate energy use in commercial buildings located in hot, arid climates. Finally, embracing renewable energy sources through adopting Photovoltaic (PV) Panels will meet remaining energy needs after energy efficiency strategies have been applied. To summarize, the main focus is on designing energy efficiency strategies rather than focusing on technologies. After conducting this research, the following results were achieved in the simulation and calculation: 1. The energy savings were beyond expectation at 150,036 kWh in remaining energy. 2. A utility bill savings of more than half the cost of building operations. 3. The simple payback on the entire solar panel system for the proposed design will be approximately 3.3 years.