Behavioural studies with cockatiels (Nymphicus hollandicus) in captivity are scarce. Due to the need for appropriate management of these animals, this study was performed to examine the behaviour of cockatiels kept in captivity at two temperatures. Sixteen cockatiels were individually housed in cages (62cm high x 43cm long x 27cm wide) and fed with a commercial ration and seed mixture for psittacids. Water was provided ad libitum. The eight-day experiment was divided into two stages of four days each. In the first stage, the birds were kept at room temperature (25°C) with 70% relative humidity during 24 hours. In the next stage, they were kept at 35°C from 06:00 to 18:00h and 25°C from 18:00 to 06:00h, also at 70% relative humidity. The behaviour of the birds was assessed by the analysis of video recordings taken from 6:00 to 18:00h. Lateral displacement on the perch, walking on the wire net, resting on the abdomen, stopping on the wire net, standing on the drinker or feeder, seed intake, cleaning the wings and shaking the plumage were not influenced (P>0.08) by temperature. Undesirable activities such as gnawing the perch or the wire net also showed no influence of temperature (P>0.15). At 35°C, the birds remained on the cage floor less often (P<0.02) and more often on the perch. Flapping or gnawing the feeder increased as did the consumption of ration (P<0.01). Increase in temperature from 25 to 35°C changed the behaviour of the cockatiels, although these behaviours were not characterised as responses to temperature stress.