Low noise stable lasers have far-reaching applications in spectroscopy, communication, metrology and basic science. The Pound-Drever-Hall laser stabilization technique is widely used to stabilize different types of lasers in these areas. Here we report the demonstration of an integrated Pound-Drever-Hall system that can stabilize a low-cost laser to realize a compact inexpensive light source, which can ultimately impact many fields of science and engineering. We present an integrated architecture utilizing an electronically reconfigurable Mach-Zehnder interferometer as the frequency reference to reduce the frequency noise of semiconductor lasers by more than 25 dB and the relative Allan deviation by more than 12 times at 200 μs averaging time. Compared to the bench-top implementations, the integrated Pound-Drever-Hall system has significantly lower power consumption, less sensitivity to the environmental fluctuations and occupies an area of only 2.38 mm2. The photonic and electronic devices are integrated on a standard 180 nm complementary metal-oxide semiconductor silicon-on-insulator process.