Purpose – Vietnam's commercial banking sector faces mounting pressure to move beyond green messaging toward genuine environmental practice, yet how green marketing converts into lasting customer loyalty is poorly understood especially in provincial markets where trust is shaped as much by communal norms and long-standing institutional relationships as by marketing stimuli. This study examines whether and through which psychological mechanisms green marketing drives customer loyalty among commercial bank users in Quảng Ngãi province. Specifically, it tests green trust and customer commitment as sequential mediators and environmental awareness as a moderating variable that conditions the strength of those mediating pathways.

Design/methodology/approach – A quantitative cross-sectional survey was administered to financial service customers across Quảng Ngãi during March–April 2026. Of 345 usable responses, 317 confirmed active use of commercial banking services and constitute the analytical sample. Green marketing was operationalized as a second-order reflective-formative construct with three first-order dimensions, such as green internal process (GIP, 3 items), green product development (GPD, 3 items), and green corporate social responsibility (GCSR, 2 items after item removal) adapted from Lymperopoulos et al. (2012) and Papadas et al. (2017). Scales for green trust, customer commitment, customer loyalty, and environmental awareness were adapted from Chen (2010), Morgan and Hunt (1994), Oliver (1999), and Straughan and Roberts (1999), respectively. A two-stage Partial Least Squares Structural Equation Modeling (PLS-SEM) approach in SmartPLS 4.0 was used to handle the second-order construct, with 5,000-subsample bootstrapping for inference on direct paths, indirect effects, and interaction terms.

Findings – Seven of eight hypotheses were supported. Green marketing positively predicted green trust (β = 0.460, f² = 0.209, p < 0.001) and customer commitment (β = 0.277, f² = 0.067, p < 0.001). The trust-to-commitment path was the model's largest effect (β = 0.494, f² = 0.390, p < 0.001), and customer commitment exerted a substantially stronger direct influence on loyalty (β = 0.377) than green trust did (β = 0.148). The hypothesized direct path from green marketing to loyalty was not significant (β = −0.056, p = 0.330), indicating that the relationship is fully mediated—operating through three statistically significant indirect routes: GM→GT→CL (β = 0.033, p = 0.039), GM→CC→CL (β = 0.086, p < 0.001), and the serial chain GM→GT→CC→CL (β = 0.086, p < 0.001). Environmental awareness positively moderated both the green marketing–trust (β = 0.151, p = 0.012) and green marketing–commitment relationships (β = 0.131, p = 0.016). Adjusted R² was 17.9% for green trust, 48.4% for customer commitment, and 20.9% for customer loyalty.

Originality/value – This study makes three contributions. First, it provides the first empirical evidence of full mediation and serial chain mediation (GM→GT→CC→CL) in the green marketing–loyalty relationship within Vietnamese commercial banking, resolving conflicting findings from prior research that assumed a direct marketing–loyalty path without accounting for the high-trust, high-asymmetry nature of financial services. Second, by simultaneously integrating Signaling Theory, the S-O-R framework, Commitment-Trust Theory, and Oliver's four-stage loyalty model, it offers a more theoretically complete account than single-framework studies have provided. Third, environmental awareness is tested and confirmed as a boundary condition in this sector for the first time in Vietnam, opening a segmentation dimension that has practical as well as theoretical implications. The Quảng Ngãi context, which is a rapidly growing provincial economy at an early stage of green finance development extends the geographic and institutional range of existing evidence, which has concentrated on major urban centers and mature banking markets.

Practical implications – Because the direct green marketing–loyalty path is blocked, bank managers cannot rely on advertising campaigns to drive retention: investment must flow upstream into verifiable environmental practice published ESG metrics, certified green credit portfolios, and digitalized operations that generates the green trust customers require before committing to a relationship. Green product design should be anchored in local economic realities rather than adapted from national templates, with distinct product architectures for the province's industrial exporters, agricultural and fishing households, and urban retail customers. Shared-value programs that engage customers as active participants rather than passive audiences in the bank's sustainability agenda are the most direct route to the commitment levels that sustain long-term loyalty. Customer segmentation by environmental awareness should inform communication strategy: technically detailed ESG disclosure for high-awareness clients, and locally grounded benefit narratives for the retail majority.

Social implications – Strengthening the effectiveness of green marketing in provincial Vietnamese banking markets can accelerate the reallocation of credit toward genuinely sustainable economic activities, supporting Vietnam's nationally determined contributions on climate change and the green finance targets embedded in the 2021–2030 National Socioeconomic Development Strategy. In Quảng Ngãi specifically, where agriculture, fisheries, and coastal ecosystems are directly exposed to climate risk, a banking sector that earns customer trust through environmental integrity rather than symbolic gestures can play a meaningful role in building local ecological resilience. The moderation finding also suggests that banks' green marketing efforts may have positive spillover effects on environmental awareness across the customer base over time.