This chapter deals with the tensile behavior of cotton fiber with the main objective being to point out some of the key challenges facing understanding the tensile failure of cotton fiber and characterization techniques. Specific subjects discussed include: fiber tensile behaviour during cotton handling (e.g. harvesting through weaving), the effect of fiber tensile strength on yarn strength, effects of fiber structure on tensile strength, tensile testing techniques, and external factors influencing the characterization of cotton tensile behavior. These subjects are discussed using examples of medium-staple and extra-long staple (ELS) cottons.