A survey of butterflies has been undertaken within the Bukit Timah Nature Reserve (BTNR), Singapore, and in the adjacent well-vegetated areas that form a buffer to BTNR, namely Hindhede Park, Singapore Quarry and the Dairy Farm Nature Park. Sampling was mainly though observations and photographic records along the transects in BTNR, and through baiting (mainly at Dairy Farm). More butterfly species (85) were recorded from the buffer areas, which have more open, sunnier secondary forest with more conspicuous food sources for adult butterflies, than there were from BTNR (63). Despite the high plant species richness at BTNR, the butterfly diversity observed within the forest transects was rather low. The greater butterfly diversity at Dairy Farm Nature Park is attributable in part to higher abundance of nectar sources (flowering trees and bushes, including many non-native plants growing along the forest edge and along open trails and footpaths). However, there are likely to be more species within BTNR, such as in the tree canopy, that were beyond the sampling scope of this survey.