Nickel laterite ores supply nearly 70% of global Ni production. They are regolith units formed by intense weathering of mostly serpentinized olivine-rich ultramafic rocks in which Ni and, commonly, Co have been concentrated to over 1.0 wt% and 0.3 wt%, respectively. A few are also residually enriched in Sc and PGM. There are three main styles of deposit, defined by the principal host minerals, namely oxide (Ni and Co hosted by Fe and Mn oxyhydroxides), hydrous silicate (Ni in serpentine, “garnierite,” nepouite) and clay silicate (Ni in smectitic phyllosilicates). The genesis, mineral composition and grades of the ores are controlled by the interaction of bedrock lithology, tectonic and climatic history, and geomorphological setting. Many Ni laterites have a multi-stage development, evolving as their climate and/or topographic settings change over time. The richest deposits (>3 wt% Ni) occur in tectonically active regions, especially island arc terranes in SE Asia-Oceania and the Antilles. Here, successive episodes of faulting and epeirogeny have uplifted the landscape, resulting in Ni being leached from the upper, oxide-rich horizons and re-concentrated in actively forming hydrous silicates in the saprolite and saprock. Brief descriptions of the Lapaopao oxide-hydrous silicate deposit, Sulawesi, and the Sunrise oxide deposit, NSW, Australia, illustrate some key features of Ni-Co laterite ores.