Adult emergence, oviposition and larval behaviors of the teak beehole borer (Xyleutes ceramica), a major pest moth of teak, were studied in the laboratory and the plantations in northern Thailand. Adult moths emerged mostly in March prior to the beginning of the rainy season. Females laid the greatest number of eggs on the first night after mating. Cumulative percentage of deposited eggs reached 79.2% on the 2nd night. The number of deposited eggs, which was estimated from weight, was 12,489 per female ranging from 3,666 to 21,094. A highly significant linear relationship existed between the numbers of eggs and the weight of an egg batch. Mated female longevity was 7 days on average. Eggs were laid in a mass mostly beneath the scales of bark of teak trunks in the field. An ovipositing female staying on a young teak tree in nature was also observed dropping her eggs to the ground. This is the first record of the finding of eggs and the oviposition behaviors of the moth in the field. Experimentally released larvae showed positive geotaxis both on the cut logs and on the living teak trunks. On the living teak trunks, larvae frequently changed their boring sites before June, but in early July, 37.5% of surviving larvae remained in the same boring sites as in the previous month and 78.6% in early August. All larvae settled down in particular boring sites in September. Control tactics for the teak beehole borer were also discussed in view of the oviposition behaviors.