International audience ; Introduction As a forest species, genetic variability is high in teak (Tectona grandis) and domestication of the species is very recent. The selection effect among qualitative and quantitative traits is therefore expected to be strong. Native provenances and clonal seed orchard families were compared in this study. Materials and methods Forty-one genetic origins of teak, including 26 open-pollinated families from a clonal seed orchard in Ivory Coast, were planted in 1997 in a replicated trial at Taliwas, Sabah, East Malaysia. Results and discussion The mortality rate and early measurements of height, and diameter at breast height varied substantially between treatments. The largest height (>18 m) and diameter (>21 cm) values recorded after 104 months were mostly from the clonal seed orchard families, while the lower performances were mainly observed for the native provenances. Narrow sense heritabilities, assessed for the clonal seed orchard families only, increased gradually with age, reaching relatively high values, especially for height at 104 months (h(2)=0.76). There were also some highly significant differences between the 41 genetic origins for six qualitative traits observed from 25 to 104 months. Overall, the clonal seed orchard families were marginally less crooked and grew more vertically than the other sources. Conclusions These findings provide further evidence of the usefulness of a clonal seed orchard phase in the genetic improvement of teak and the beneficial influence of a wet tropical climate on major economic traits.