Bipolar disorder is known to be a group of affective disorders depicted by depressive manic or hypomanic disorders. Indeed, considered as an oldie as its pharmaceutical usage started in the 19th -century lithium is also a goodie used as the first-line treatment for bipolar disorder. In addition, it is considered to be the only treatment with anti-suicidal effects. During treatment, lithium levels should be monitored as its therapeutic levels (0.5-0.8 mM) in the blood are close to intoxication levels (>1.5 mM) and to severe intoxication levels > 2.5 mM, which might induce coma. That is why it is necessary for patients diagnosed with bipolar disorder to monitor lithium levels frequently. In fact, there are many traditional analytical techniques for lithium detection. Still, these are associated with limitations as they are very expensive, time-consuming, and not found in all laboratories. So, the need to develop a cost-effective, sensitive, and easy-to-handle devices has grown. Affinity sensors constitute a promising potential for the sensitive detection of lithium. This review, to my knowledge, is the first review highlighting the different types of biosensors developed for lithium-ion detection while explaining the mode of action of each biosensor