Acacia mangium is favored for commercial planting in Northern and North-central Vietnam to produce wood chip for pulp production and wood chip export also timber for furniture industry. In order to implement a successful genetic improvement program of A. mangium in Vietnam, it is necessary to understand genetic variation of economically important traits in this species in Vietnam. This study was conducted in a progeny trial at Ba Vi, Hanoi which included 84 families from 9 natural provenances and a clonal trial included 90 clones at Cau Hai, Phu Tho province. Results of the study showed significant differences between provenances, families and clones tested. This suggested considerable genetic variation between provenances, families and clones. Therefore, genetic improvement can be achieved through selections in provenance, family and individual levels. Growth and stem form traits had intermediate heritabilities (0.10 - 0.36) relatively high coefficient of genetic variation. This suggested a remarkable genetic gain can be achieved through breeding and clonal deployment activities. Strong phenotypic correlation between growth traits and stem straightness indicated selection for increased productivity will also improve stem form in A. mangium.