Background: Higher Education Institutions are mandated to deliver extension as a core function, yet the sustainability of partnerships is rarely examined through an axiological lens. Purpose: This study assessed HEI-community partnerships in Zamboanga City across assessment (inputs, process, outcomes), monitoring, and evaluation as basis for a sustainability plan. Methods: A descriptive-quantitative survey of 223 stakeholders (28 BLGU officials, 2 key persons, 2 staff, 191 beneficiaries) from four adopted barangays of one public and one private HEI used a validated AACCUP-based instrument (α=0.986). Data were analyzed using weighted mean, independent t-test, and ANOVA. Results: Partnership was Extensive for inputs (M=3.66), process (M=3.62), monitoring (M=3.52), evaluation (M=3.56) and Moderate for outcomes (M=3.50), overall M=3.59 (Extensive). Significant differences existed by HEI type (private > public, p<0.05) and respondent type (staff/key persons > beneficiaries, p<0.001). Conclusion: Partnerships are structurally sound but outcome-moderate, revealing a gap between delivery and institutionalized transformation. A five-pillar sustainability plan anchored on legitimacy, reciprocity, and distributive justice is proposed.