ABSTRACT The demand for sustainable digital and information systems requires a transformative shift in software engineering practices that balance technical performance with economic, environmental, and social responsibility. This paper introduces LAGSSE, which is a novel framework that integrates Lean, Agile, and Green principles to advance Sustainable Software Engineering (SSE). LAGSSE operationalizes six interconnected sustainability dimensions: technical, environmental, economic, social, process, and infrastructure through a layered architecture and lifecycle‐based approach, underpinned by the OntoSuSD ontology for semantic clarity and traceability. A two‐phase validation strategy confirms the framework's strength; that is, a Delphi‐based expert study ( n = 75) establishes conceptual clarity and applicability, while simulation‐based evaluations demonstrate measurable improvements in energy efficiency (25%), defect reduction (33%), deployment speed (30%), and stakeholder satisfaction (24%) compared to baseline Agile practices. Visual models, statistical charts, and a Sustainability Performance Score (SPS) equation reinforce the framework's empirical grounding and practical utility. This framework not only addresses critical gaps in existing SSE frameworks but also provides an adaptable, comprehensive, and validated pathway for embedding sustainability into software engineering education, industry practice, and policy development.

Abstract Different software development approaches (SDAs) are developed with broad portfolios of development processes. Each of the approaches has certain exclusive principles, practices, thinking, and values, which are informally represented, implemented, and improperly institutionalized. Ontologies are developed for the representation, assessment, and adaptation of SDAs separately without having a shared terminology which may lead to terminological conflict and confusion affecting the simultaneous representation and implementation in software development industry and academia. The software engineering approaches does not consider and support sustainability as priority concern. However, the approaches have capabilities of supporting sustainable software development in different sustainability aspects. This research article aims for the designing and development of an integrated ontology of software engineering approaches (i.e., agile, lean, and green) named OntoSuSD (ontology for sustainable software development) to support sustainable software development knowledge, awareness, and implementation. The goal of OntoSuSD is to propose, design and develop a formal, generic, consistent, and shared knowledge base containing semantic terminology and description of concepts and relationships generated around the representation and implementation of lean, agile, and green approaches in software development processes, which will facilitate their simultaneous implementation and assessment for sustainable software development. The OntoSuSD is developed using practical ontology engineering methodology by reusing relevant ontologies and explicit concepts and properties are defined to fulfill knowledge requirements and representations of the domain. The OntoSuSD is evaluated, and results infer OntoSuSD has high ontological design, good domain coverage, potential applications and achieves purpose of the ontology development.