The organ in the human body responsible for producing insulin is the pancreas. This glandular organ plays a vital role in regulating blood sugar levels by secreting insulin, a hormone essential for allowing cells to absorb glucose for energy. The pancreas has both endocrine and exocrine functions, with the endocrine function producing insulin and glucagon to manage blood sugar levels. Dysfunction in insulin production can lead to conditions such as diabetes mellitus, highlighting the importance of the pancreas in maintaining metabolic and overall health.