Recent findings highlighted the potential of long non-coding RNAs (lncRNAs) as novel indicators of gestational diabetes mellitus (GDM), as they demonstrate altered expression in metabolic disorders, oxidative stress (OS) and inflammation (IFM). The aim of this study was to evaluate the diagnostic potential and prognostic significance of the OS/IFM-related lncRNAs H19, MALAT1 and MEG3 in GDM and their correlations with redox status-related parameters. The relative quantification of selected lncRNAs from peripheral blood mononuclear cells (PBMCs) of GDM patients and controls (n = 50 each) was performed by qPCR. The expression levels were tested for correlations with metal ion concentrations, NRF2 expression, activities of glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT), serum thiol content, protein carbonyl level and thiobarbituric acid reactive substances. MALAT1 and H19 were significantly downregulated in GDM patients (p = 0.0095 and p = 0.012, respectively). A correlation was observed between H19 expression and zinc levels in both GDM patients and controls. MALAT1 expression positively correlated with NFE2L2 levels in GDM patients (p = 0.026), while H19 exhibited a positive correlation with GR activity in controls (p = 0.018) and an inverse correlation with SOD activity (p = 0.048). Our data show the disturbance of OS/IFM-lncRNAs in GDM pathogenesis and illustrate the biomarker potential of the analyzed lncRNAs, as well as of certain redox status parameters.