Public procurement accounts for a substantial proportion of national expenditure in developing economies, frequently representing between fifteen and thirty per cent of gross domestic product. This concentration of spending positions government purchasing as a powerful lever for shaping markets, advancing social objectives and protecting the natural environment. At the same time, the central accountability standard against which public spending is judged remains value for money, conventionally understood through the economy, efficiency and effectiveness with which resources are converted into outcomes. A persistent tension is assumed to exist between the additional costs associated with sustainable procurement and the cost minimisation that value for money is presumed to demand. This paper interrogates that assumption. Drawing on a structured narrative synthesis of literature published mainly from 2017 onward, the study advances a conceptual analysis of how the three principal dimensions of sustainable public procurement, namely environmental, social and economic practices, influence value for money in the public sector of developing economies. The analysis integrates institutional theory, stakeholder theory, the resource-based view and the triple bottom line to explain the mechanisms through which sustainability considerations reshape, rather than merely inflate, the value calculus. The paper argues that when value for money is reframed around whole life cost and broad public value rather than lowest acquisition price, sustainable procurement practices become complementary to, rather than in competition with, value for money objectives. A conceptual framework and a set of testable propositions are proposed, in which organisational capability mediates the relationship, while leadership commitment, supplier market maturity and regulatory clarity act as boundary conditions that moderate it. The study contributes a coherent theoretical account suited to resource constrained contexts and offers an agenda for empirical validation. Implications for theory, public policy and procurement practice are discussed.