Energy saving becomes a controversial issue with development of technology. There have been control systems to save the energy, and among these, the thesis focuses on the development of an indoor lighting control system to save the lighting energy consumption since the lighting systems annually consumes approximately 30% of the energy consumed by lighting systems in a building. The main aim of the indoor lighting control system is to create a constant light level – this is referenced by user - in a given zone irrelative to the disturbance signals coming from other sources such as natural light, by using sensors, LEDs and a dimming switch. Most control systems shall be tested during development, and an actual building or subject – plant in control engineering filed – is required to simulate the lighting control system. Yet, assessment of a prototype system by actual subjects may damage the electronic equipment used and lead fatal errors due to the uncertainty of the system, and also it may delay the time since the modification of the actual subjects is limited with constraints. These problems ultimately cost a lot of budget. Not to waste the cost and minimize to damages, this thesis applies Hardware-in-the-loop simulation technology to simulate the indoor lighting control system which is under development at Budapest University of Technology and Economics in real-time. The HIL method is to create a simulated plant which responses as the real plant. This way allows obtainment of the information same as we would collect from the real plant when injecting conceivable error and further modification of parameters. Eventually, by developing this indoor lighting control system, the indoor light level will be controlled as a constant level by applying not only the light sources in a building, but also the daylight. In addition, the energy consumed by lighting systems will be increasingly decreased.