Abstract: Demand for nickel (Ni) and cobalt (Co) is rising, with laterite deposits being an increasingly important source. However, current processing methods (e.g., smelting or high-pressure acid leaching) are energy-intensive and pose environmental hazards. To address this challenge, there has been increasing interest in chloride leaching, particularly with HCl, due to its flexibility and efficacy at ambient conditions. To date, much of the focus on advancing the chloride leaching technology has been on the downstream separation and recovery stages, to overcome its inherent disadvantages, such as a high acid-to-ore ratio, impure leachates due to non-selective leaching, and difficulties in Ni-Co purification (e.g., co-adsorption losses). Nonetheless, effective metal extractions depend on understanding the underlying behavior of ore minerals during acid dissolution. The deportment of target metals (Ni-Co) and impurities, and their leaching mechanisms, remains poorly understood. Given the complex mineralogy of laterites, information on how minerals behave in HCl leaching is paramount to improve leaching efficiency. This study reveals that metal extraction during HCl leaching (8 mol/L, 3 hours, 95 °C, ambient pressure) is uneven and controlled by specific ore minerals. The release of Ni is governed by its distribution in acid-soluble minerals asbolane (Mn-hydroxide), Fe oxyhydroxides (e.g., goethite), chlorite, serpentine, and clay minerals (Ni-bearing smectite group) in the laterite feed. Conversely, for Co, although predominantly hosted by acid-soluble minerals (asbolane, with minor contributions from Fe oxyhydroxides and chlorite), it is also present in insoluble chromite. Deportment of Co in chromite varies from around 2 to 55% in the laterite ores. Examination of leaching residues confirms that HCl effectively dissolves most ore minerals, except refractory chromite. Therefore, chromite retention in the residue sequesters part of the Co content and prevents the total Co recovery during atmospheric HCl leaching. Overall, this work highlights the vital role of mineral-specific dissolution mechanisms in controlling metallurgical performance. This knowledge is crucial for flowsheet development, enabling precise adjustment of leaching steps to target ore minerals, account for mineralogical factors that limit recovery, and thereby maximize metal yield.