The interaction of water with food packaging is a critical aspect of food preservation, quality, and safety. Packaging materials must be carefully chosen to prevent moisture from entering or leaving the package, as moisture can affect the texture, taste, and safety of the food. Several methods are employed to gain a thorough understanding of the interaction between water and food packaging. The selection of a particular method depends on the specific properties under investigation and the objectives of the analysis. This chapter is dedicated to exploring the measurement of contact angle, a key parameter in assessing the interaction between water and food packaging materials.