Patterns in vegetation phenology and their connection to climatic variables are one of current central topics in studying ecosystem response to global climate change. The timing and magnitude of flowering and fruiting impact pollinators and frugivores and seasonal patterns of litterfall and radial stem growth affect the carbon and nutrient cycling. We reported the phenological patterns of reproduction, litterfall and vegetative growth and the factors affecting those patterns in an aseasonal Bornean tropical rainforest, using phenology observation (ca. 18 years), litter-trap (16 years), annual tree census (16 years), and climate (23 years) data in Lambir Hills National Park, Sarawak, Malaysia. General flowering and fruiting (GF), community-wide masting, were observed 10 times in 23 years and flowering frequency differed largely among tree species. Time-series analysis identified that drought and low air temperature cause GF. Litterfall showed intra- and inter-annual fluctuations and the amount of leaffall tended to increase gradually. Radial stem growth and aboveground biomass increment also seemed to be inconstant responding to GF events and/or climatic variables. Long-term monitoring data indicate fluctuating phenological patterns in a tropical rainforest where seasonal climatic variation is week.