Justus Freiherr von Liebig (12 May 1803 – 18 April 1873) is a German chemist who makes major contributions to agricultural and biological chemistry, and works on the organization of organic chemistry.

As a professor, he devises the modern laboratory-oriented teaching method, and for such innovations, he is regarded as one of the greatest chemistry teachers of all time.

He is known as the "father of the fertilizer industry" for his discovery of nitrogen as an essential plant nutrient, and his formulation of the Law of the Minimum which describes the effect of individual nutrients on crops.

He also develops a manufacturing process for beef extracts, and founds a company, Liebig Extract of Meat Company, that later trademarks the Oxo brand beef bouillon cube.