Thyroid hormones (THs) T3 and T4, play an essential role in the development and metabolism of many tissues and organs, and have profound metabolic effects in adult life. THs action is mediated mainly by the thyroid hormone receptor (TRs) which seem to be ubiquitous. To-date thyroid-associated disease are not thought to be related in tendinopathies and tendons tears. Recent study demonstrated the presence of TRs in tendons and their possible role in the proliferation and apoptosis of human tenocyte isolated from tendon. We review new discovery that revisit our current thinking on the tendon biology focusing on thyroid hormones (THs) T3 and T4, and their possible role on human tenocyte.