Metallothioneins (MTs) are low weight proteins involved in several key cellular processes such as metal ions homeostasis, detoxification and scavenging of free radicals. Four groups of MTs are distinguished: MT-1, MT-2, MT-3 and MT-4. Regardless of the type, MTs are characterized by high content of cysteine, responsible for their biological properties such as binding of relevant zinc and copper ions, as well as toxic ions such as lead and cadmium. MTs were additionally shown to protect cells against oxidative stress damage and participate in differentiation, proliferation and/or apoptosis of normal and cancer cells. Many studies of different neoplasms showed association of elevated MTs levels with occurrence of chemo- and radiotherapy resistance and poor patients' outcome. In this review, we summarize and discuss the potential mechanism of action of metallotioneins in lung physiology and pathology.