The depletion of fossil fuel reserves and the rise in greenhouse gas emissions are spurring the development of renewable energy technologies. Lignin, a key component of biomass, holds promise due to its potential to yield valuable chemicals and alternatives to fossil fuels. This chapter delves into lignin’s utilization in composite materials for photocatalysis, highlighting its role as a support for photocatalysts in contaminant degradation. The interaction between components in hybrid photocatalysts is crucial for optimizing photocatalytic performance.