Objective: To investigate the association between myopia and ganglion cell layer and inner plexiform layer (GCIPL) in diabetic population without diabetic retinopathy (DR). Methods: In this Guangzhou Diabetic Eye study, a total of 1 165 patients aged 30–80 years were recruited followed up longitudinally for 2 years. According to the presence or absence of myopia [spherical equivalence (SE)≤-3 diopter (D)] and diabetics, the patients were divided into a healthy group (n=508), a diabetes mellitus group (n=525), and a diabetes mellitus + myopia group (n=132). GCIPL was measured via swept-source optical coherence tomography. Univariable and multivariable mixed models were used to show the association of GCIPL change and baseline parameters. Results: SE was (1.07±1.06) D in the healthy group, (1.02±1.00) D in the diabetes mellitus group and (-5.36±2.30) D in the diabetes mellitus + myopia group (P<0.001). The baseline GCIPL thickness were (71.1±0.3), (74.4±0.2), and (71.7±0.5) μm, respectively. The slope of GCIPL thickness was -0.10 (95% CI: -2.03 to 0.05) μm/year in the healthy group, which was 12 folds faster than those in the diabetes mellitus group [-1.21(95% CI: -24.04 to 0.05 μm/year, P<0.001] and 22 folds higher among those in diabetes mellitus + myopia group [-2.17 (95% CI: -21.63 to 0.10) μm/year, P=0.009]. Conclusion: Both myopia and diabetes status accelerate macular ganglion cell layer and inner plexiform layer thinning in diabetic patients without diabetic retinopathy.