<p>The transition toward a circular economy requires robust sustainable supply chain performance (SSCP) evaluation frameworks, yet Small and Medium Enterprises (SMEs) face persistent challenges due to resource constraints and the absence of integrated, accessible assessment tools. This study develops and validates a novel integrated framework combining Entropy weighting, Data Envelopment Analysis (DEA), and Capability Maturity Model (CMM) classification to evaluate and benchmark SSCP in manufacturing SMEs. The Entropy method objectively weights multiple input indicators, Supply Chain Agility, Analytics Capability, Resilience, and Sustainable Supply Chain Ambidexterity, and output indicators encompassing economic, operational, and environmental performance dimensions. Subsequently, input-oriented and output-oriented CCR DEA models measure relative efficiency, while super-efficiency and cross-efficiency analyzes provide robust benchmarking. Finally, efficiency scores are translated into a five-level maturity classification, transforming quantitative gaps into stage-specific improvement pathways. Empirical application to ten manufacturing SMEs reveals significant performance heterogeneity, with efficiency scores ranging from 0.493 (Level 1/Initial) to 1.000 (Level 5/Optimized). Slack analysis identifies that inefficiencies predominantly stem from input redundancies in Analytics Capability and Sustainable Supply Chain Ambidexterity, rather than output shortfalls. The framework contributes theoretically by integrating three complementary methodologies into a unified diagnostic system that bridges performance measurement and developmental roadmap. Practically, it offers managers and policymakers a structured, evidence-based tool for identifying capability gaps, prioritizing resource allocation, and designing stage-appropriate improvement strategies tailored to each SME’s maturity level, ultimately supporting their sustainable transition within circular economic imperatives.</p>