Purpose: To evaluate the vascular anatomy of eyes with Best vitelliform macular dystrophy (BVMD) using optical coherence tomography angiography (OCTA). Methods: This retrospective case-control study enrolled 11 consecutive BVMD patients and 13 age-matched healthy participants. Both eyes of each participant were imaged using a macular OCTA scan (3 x 3 mm) by 70-kHz 840-nm spectral-domain OCT. The flow signal was calculated using the split-spectrum amplitude-decorrelation angiography (SSADA) algorithm. Results: Qualitative analysis showed uneven hypo- and hyperintense signal changes at the choriocapillary level in OCTA images of BVMD patients. Quantitative analysis showed significant reductions in the flow density of the superficial vascular layer (whole: 49.2% vs. 53.9%, p < 0.001) and the choriocapillary flow area (5.1 vs. 5.5 mm(2), p = 0.02) in BVMD patients compared to controls. The choriocapillary flow area in the postvitelliform group was reduced compared to that of the vitelliform group. There was a statistically significant association between choriocapillary flow area and superficial vascular flow density (p = 0.045), choriocapillary flow area and foveal avascular zone area (p = 0.03). Conclusions: Vascular changes in BVMD were apparent in the choriocapillary layer. The changes became more striking in late stages of the disease. OCTA provides useful quantitative measurements for staging and monitoring the progression of BVMD.