Gestational diabetes mellitus (GDM)is one of the most common perinatal pathologies, with a prevalence of 5–20% depending on the population or diagnostic standards. It is diagnosed when glucose intolerance is first detected during pregnancy. In the pathogenesis of GDM, genetic, environmental, and pregnancy-related factors (excessive fat storage and increased adipokine and cytokine secretion) play important roles. A growing amount of scientific data has indicated the role of gut microbiota (GM) dysbiosis in the development of glucose intolerance during pregnancy. Previous studies have indicated that, in comparison to healthy pregnant women, GDM individuals have a greater abundance of bacteria belonging to the genera Ruminococcus, Eubacterium, and Prevotella and a lower number of bacteria belonging to the genera Bacteroides, Parabacteroides, Roseburia, Dialister, and Akkermansia. Recently, many studies have focused on treating GDM with methods targeting GM. Several previous studies have analyzed the effect of probiotics on the course of GDM, but their data are inconclusive. In view of this state, the aim of the study was to collect and comprehensively discuss current knowledge regarding the role of probiotic supplementation in preventing and treating GDM. According to the analyzed data, probiotics have a positive influence on glycemic control and are a promising tool for lowering the frequency of GDM. However, further studies must be conducted to determine the optimal model of probiotic therapy (strain, dose, time of intervention, etc.) in pregnant women with GDM.