Introduction: With efforts to combat opioid use disorder, there is an increased interest in clinical practice guidelines (CPGs) for opioid use disorder treatments. No literature exists examining the quality of systematic reviews used in opioid use disorder CPGs. This study aims to describe the methodological quality and reporting clarity of systematic reviews (SRs) used to create CPGs for opioid use disorder. Methods: From June to July 2016 guideline clearinghouses and medical literature databases were searched for relevant CPGs used in the treatment of opioid use disorder. Included CPGs must have been recognized by a national organization. SRs from the reference section of each CPG was scored by using AMSTAR (a measurement tool to assess the methodological quality of systematic reviews) tool and PRISMA (preferred reporting items for systematic reviews and meta-analyses) checklist. Results: Seventeen CPGs from 2006–2016 were included in the review. From these, 57 unique SRs were extracted. SRS comprised 0.28% to 17.92% of all references found in the CPGs. All SRs obtained moderate or high methodological quality score on the AMSTAR tool. All reviews met at least 70% of PRISMA criteria. In PRISMA, underperforming areas included accurate title labeling, protocol registration, and risk of bias. Underperforming areas in AMSTAR included conflicts of interest, funding, and publication bias. A positive correlation was found between AMSTAR and PRISMA scores (r = .79). Conclusion: Although the SRs in the CPGs were of good quality, there are still areas for improvement. Systematic reviewers should consult PRISMA and AMSTAR when conducting and reporting reviews. It is important for CPG developers to consider methodological quality as a factor when developing CPG recommendations, recognizing that the quality of systematic reviews underpinning guidelines does not necessarily correspond to the quality of the guideline itself.