Purpose: This study aimed to determine the effectiveness of Pilates on pain and disability in adults with chronic nonspecific low back pain (CNSLBP) and to explore effects by intervention duration and type (mat-based vs. equipment-based). Methods: A systematic review and meta-analysis of randomized controlled trials (RCTs) following PRISMA 2020 was conducted. Eligible studies enrolled adults with CNSLBP, compared Pilates with non-Pilates comparators, and reported pain and/or disability outcomes. Searches covered PubMed, Embase, Cochrane Library, and CINAHL plus Korean databases (RISS, DBpia, ScienceON) from inception to September 14, 2024. Risk of bias was assessed with the Cochrane Risk of Bias 2 tool. Random-effects models generated standardized mean differences (SMD) with 95% confidence intervals (CI). Publication bias was assessed for outcomes with at least 10 studies. PROSPERO (CRD42024582637). Results: A total of 10 RCTs (n = 802) were included. Pilates reduced pain versus controls (SMD: −1.25, 95% CI: −1.70; −0.80, I²: 77%) and reduced disability (SMD: −0.78, 95% CI: −1.23; −0.34, I²: 79.7%). By duration, 5–8-week interventions improved both pain and disability, whereas interventions of 4 weeks or less showed no improvement in disability. By type, both mat-based and equipment-based Pilates improved pain and disability, with no significant subgroup differences. Conclusion: Pilates is effective for improving pain and disability in CNSLBP, with improvements most prominent over 5–8 weeks and across both mat-based and equipment-based formats. However, evidence for equipment-based Pilates is limited, and high-quality RCTs assessing longer-term and equipment-based Pilates interventions are needed.