Bipolar disorder is known to have a heterogeneous disease course, where a subgroup of patients may present biological changes in the brain and periphery, including changes in neuroanatomical structure, inflammatory markers, and markers of oxidative stress. As the disease progresses, the clinical and biological changes associated with mood episodes become more pronounced, increasing the patient’s vulnerability to stress and new episodes, which, in turn, reinforces the cycle of progressive changes in bipolar disorder, which is called neuroprogression. This chapter aims to review the literature on biomarkers that have been associated with neuroprogression in individuals with bipolar disorder.