Purpose: to demonstrate the connection between a lack of vitamin D and dry eyes and to assess how vitamin D supplements affect both dry eyes and tear production. Methods: A total of 60 patients (120 eyes) attending Benghazi Teaching Ophthalmology Hospital were enrolled in the study, during the period from February 2021 to October 2021. The ocular surface disease index, the time test, and the schirmer test were used to evaluate each participant. For the examination of the serum vitamin D, blood samples were taken. Results: There was significant increase in Tear Film Break-Up Time (TFBUT) and Schirmer test after follow up while there was significant decrease in Ocular Surface Disease Index (OSDI) after follow up. Conclusions: Each patient's serum vitamin D levels must be checked when treating dry eye, and if they are low, a supplement may be helpful.