•Interferential current probably reduces pain intensity and disability immediately post-treatment compared to placebo in patients with chronic non-specific low back pain.•Interferential current may reduce pain, but not disability, immediately post-treatment compared to other interventions in patients with chronic non-specific low back pain.•Interferential current combined with other intervention (massage or exercises) may not further reduce pain intensity and disability compared to other interventions provided in isolation immediately post-treatment in patients with chronic non-specific low back pain. There is no systematic review assessing the effectiveness of interferential current (IC) in patients with low back pain. To investigate the effectiveness of IC in patients with chronic non-specific low back pain. The databases PUBMED, EMBASE, PEDro, Cochrane Library, CINAHL, and SCIELO were searched. Randomized controlled trials reporting pain intensity and disability in patients with chronic non-specific low back pain, in which IC was applied were included. Methodological quality was assessed using the PEDro scale. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to evaluate the quality of evidence. Thirteen RCTs were considered eligible for this systematic review (pooled n = 1367). Main results showed moderate-quality evidence and moderate effect sizes that IC probably reduces pain intensity and disability compared to placebo immediately post-treatment (Pain: MD = -1.57 points; 95% CI -2.17, -0.98; Disability: MD = -1.51 points; 95% CI -2.57, -0.46), but not at intermediate-term follow-up. Low-quality evidence with small effect size showed that IC may reduce pain intensity (SMD = -0.32; 95% CI -0.61, -0.03, p = 0.03) compared to TENS immediately post-treatment, but not for disability. There is very low-quality evidence that IC combined with other interventions (massage or exercises) may not further reduce pain intensity and disability compared to the other interventions provided in isolation immediately post-treatment. Moderate-quality evidence shows that IC is probably better than placebo for reducing pain intensity and disability immediately post-treatment in patients with chronic non-specific low back pain.