This article examines the relationship between law and poverty in three African urban contexts: Nairobi, Lagos, and Johannesburg. The central theme concerns the criminalisation of survival strategies adopted by homeless persons and informal street traders. The objective is to analyse how legal frameworks, municipal by-laws, and police practices converge to penalise poverty despite constitutional guarantees of dignity and equality. The methodology adopts a qualitative, multi-jurisdictional case study design. Data were collected through doctrinal analysis of statutes, municipal by-laws, and judicial decisions from Kenya, Nigeria, and South Africa, complemented by 42 semi-structured interviews with street traders, homeless individuals, police officers, and legal advocates. The results reveal a consistent pattern of punitive governance. Colonial-era vagrancy laws are actively revived and repurposed. Municipal by-laws grant broad discretion to enforcement officers, creating legal grey zones where harassment and extortion thrive. Judicial interpretation frequently defers to executive notions of public order, limiting the protective reach of constitutional rights. The conclusion argues for a rights-based approach to urban governance. The criminalisation of poverty represents a fundamental failure of constitutionalism and undermines the project of building just and equal societies. The study contributes a novel analytical framework, the jurisprudence of precarity, to illuminate the legal logics that perpetuate urban marginalisation.