Purpose: Gestational diabetes mellitus (GDM) is fairly common in India. There is an interplay of various factors like androgens, sex hormone-binding globulin (SHBG), estrogen, and progesterone on the tear film in pregnancy. Diabetes mellitus in itself affects the lacrimal function unit (LFU) and ocular surface. This study was therefore performed to assess the effect of the various factors on the tear film function and ocular surface in GDM using different diagnostic tests. Methods: Case–control study includes 49 subjects after calculating the sample size. Cases of newly diagnosed GDM in their second or third trimester of pregnancy without any ocular or systemic comorbidities. The following standard tests were performed, namely, ocular surface disease index (OSDI) scoring, Schirmer’s test, tear film breakup time (TBUT), and ocular surface staining (SICCA). Results: The two study groups did not differ significantly in terms of age, gestational age, and presenting symptoms. None of the patients had diabetic retinopathy, and the ocular surface was unaffected in both groups. There was a significant difference in the Schirmer’s II test (P = 0.01) between the groups, while Schirmer’s I (P = 0.06) and TBUT (P = 0.07) were not significant. Conclusion: Our study suggests that GDM patients can potentially suffer from DES despite the lack of symptoms and may be the basis for conducting larger studies to justify routine screening of GDM for DES in order to improve the quality of life of pregnant women.