The business environment in Tanzania has undergone significant reform, yet persistent structural challenges continue to constrain enterprise growth and development. A nuanced, diagnostic understanding of these enduring obstacles, beyond quantitative metrics, is required to inform effective policy. This study aims to identify and analyse the key persistent challenges faced by businesses, exploring their underlying causes and interconnections from the perspective of enterprise operators and stakeholders. A qualitative, multi-method design was employed, comprising 42 in-depth, semi-structured interviews with business owners, senior managers, and industry association representatives, supplemented by focus group discussions and documentary analysis. Data were analysed using a thematic framework approach. Analysis identified a dominant, cross-cutting theme of systemic unpredictability in regulatory enforcement, which exacerbates other operational challenges. A significant proportion of participants (over 70%) cited ad hoc interpretation of regulations as a major constraint, creating an environment of uncertainty that stifles long-term investment and planning. The study concludes that the perceived unpredictability of the regulatory regime is a more profound barrier to business growth than the content of the regulations themselves, perpetuating a cycle of risk aversion and informal practices. Policy interventions should prioritise enhancing the consistency, transparency, and communication of regulatory enforcement mechanisms over further legislative changes. Establishing independent business ombudsman services and regular stakeholder consultation fora is advised. business environment, regulatory predictability, qualitative diagnostics, enterprise constraints, policy reform This paper provides a novel, longitudinal diagnostic framework for analysing business climate challenges, moving beyond static indicators to capture the lived experience of systemic unpredictability.