Pectolite has been identified, using petrographic, chemical, and X-ray methods, in kimberlites from the De Beers and Dutoitspan Mines, Kimberley, South Africa and the Letseng-La-Terai Mine, Lesotho. It occurs as radiating aggregates of fibrous or acicular crystals not only in the groundmass of certain kimberlites but also in altered xenoliths included within kimberlite. The occurrence of Na-rich minerals in kimberlite is unusual. It is suggested that it can occur as an apparently primary mineral resulting from the incorporation and assimilation of foreign Na-bearing material prior to final consolidation, and/or as a secondary mineral after metasomatic introduction of Na-bearing fluids.