A cost-effective optical fiber daylighting system using modified compound parabolic concentrators (M-CPC) and plastic optical fibers (POFs) was developed. The M-CPC, a combination of two conventional CPCs, achieved an optical efficiency of up to 84% with a concentration ratio of 100. The M-CPC design allows for a simpler and cheaper mass production process. It also has a high tolerance for sunlight angles, reducing the need for expensive sun-tracking systems. Experiments confirmed the effectiveness of the M-CPC design, making it a promising low-cost and efficient solution for solar energy applications in buildings.