Buildings in hot-arid Middle Eastern climates face an energy challenge that is structurally different from that confronted by architects in temperate zones. Cooling alone accounts for 70–80% of residential electricity consumption, driven by ambient temperatures exceeding 45°C and annual solar radiation surpassing 2,200 kWh/m²/year. Under these conditions, the standard Northern European route to net-zero performance—add insulation until the heating load disappears—does not work directly transposed: peak solar gains, urban heat island intensification, and minimal temperature gradients across envelope assemblies demand a more nuanced strategy. This review examines whether terracotta and fired-clay brick systems can contribute meaningfully to that strategy, synthesising evidence from 90 peer-reviewed studies published between 2018 and 2025. Studies were retrieved through systematic searches of Scopus, Web of Science, ScienceDirect, and IEEE Xplore following PRISMA protocols, and screened for quantitative thermal performance data from buildings in Köppen-Geiger BWh and BSh climate zones. Bio-waste-enhanced terracotta formulations incorporating 15 wt% mushroom cultivation waste (El-Hady et al., 2025) or Pleurotus florida residues combined with rice husk (Fahmy et al., 2024) reduced thermal conductivity by 32–62% relative to conventional fired-clay bricks. In residential building simulations, these materials replaced conventional concrete masonry and reduced cooling energy consumption by 12.4–38.8%. When integrated with passive design strategies—night ventilation, external shading, and thermal mass optimisation—terracotta envelope systems contributed to annual cooling load reductions of 31.8–56.4% (Kaitouni et al., 2024; Bernard-Pierrot, 2022). Economic analyses placed payback periods at 3–7 years where electricity tariffs exceed $0.10/kWh, though the economics are materially less favourable in Gulf states operating subsidised residential tariffs below $0.08/kWh. Three significant gaps constrain the conclusions this evidence can support. No regional embodied carbon data exist for terracotta manufactured within the Gulf Cooperation Council, which means life-cycle carbon comparisons rest on European and South Asian inventory data of uncertain applicability. No published study has demonstrated whole-building net-zero energy balance in a UAE or Saudi Arabian building where terracotta serves as the primary envelope material. And the measurement and simulation literature exhibits methodological inconsistencies—in thermal test protocols, climate file selection, and economic assumptions—that limit quantitative synthesis across studies. The research priorities identified here follow directly from these gaps: standardised testing protocols for bio-enhanced formulations, validated net-zero whole-building models in Gulf climates, and life-cycle assessments incorporating regional manufacturing and transport chains.