Introduction: Gestational diabetes mellitus (GDM) is defined by reduced glucose tolerance that appears or is first noticed during pregnancy. Leptin is a crucial adipokine that regulates a variety of processes, including insulin sensitivity, The main contributing factor to the emergence of GDM is insulin resistance. Objective of the study is to compare leptin levels and various insulin resistance (IR) models between GDM cases and normoglycemic pregnant women. Aim is to also find out whether leptin and IR models can be predictors of GDM. Methodology: The cross-sectional study was carried out with the inclusion of hundred each GDM and normoglycemic pregnant women. Fasting blood samples were drawn for analyzing serum leptin, insulin, C-peptide by ELISA. Suitable statistical tests were applied using Graphpad instat 3. Results: Fasting C peptide was significantly higher in cases (p=0.0014). Fasting serum insulin and leptin levels were insignificantly low in GDM patients (p=0.6968 and p=0.213). Comparison of IR models among cases and controls showed a significantly low, (p<0.0001) HOMA B cell and HOMA 1% B cell (insulin based) as well as significantly high (p<0.0001) HOMA B cell, HOMA 1% B cell(C peptide based) in cases. Conclusion: It could be concluded from the study that, leptin was insignificantly low,C-peptide and C –peptide based insulin resistance models were elevated in GDM patients. Leptin as well as various insulin resistance models were not good markers to predict GDM.