Several studies have synthesized silica from waste. The silica synthesis method from agricultural waste aims to produce high purity silica with low contaminants at an affordable cost. This study synthesized silica from oil palm boiler ash (OPBA) by various methods such as ball milling, coprecipitation, and modification with methyl trichlorosilane (MTCS). XRD characterization results showed that OPBA synthesized with ballmill and coprecipitation method has the smallest particle size of 14.90 nm. Morphology showed OPBA by ballmill method, OPBA synthesized with ballmill and coprecipitation method, and OPBA synthesized with ballmill, coprecipitation, and modified with methyl trichlorosilane as spherical particles. At the same time, the FTIR results show an absorption peak which is a characteristic of silica confirmed by XRF results, where silica content is the dominant content.