Abstract: Grouper aquaculture is a rapidly growing and dynamic industry within Vietnamese aquaculture and an important source of local employment and income generation. Information on the state of current production practices and profitability for specific crops across different geographic locations and stages of production is difficult to obtain. This research contributes to wider efforts to address this knowledge gap by providing indicative findings on current market characteristics, production practice, and profitability of a ‘new’ aquaculture crop in Vietnam: Hybrid grouper (E. lanceolatus X E. fuscoguttatus). Participants in the study identified Hybrid grouper as the most important crop for grow out farms and the second most important crop for nursery farms due to strong market demand and sales prices, fast growth rate, and higher survival compared to other grouper crops. Research utilised a survey of 12 grouper farms in the Northern (Hai Phong) and Central (Khanh Hoa) provinces of Vietnam in mid-2018 to determine indicative financial production characteristics and gross margins (annual net sales revenue minus cost of goods sold) of nursery, cage, and pond enterprises that currently culture Hybrid grouper. Farmers indicated that the Hybrid grouper industry was segmented into three distinct phases of production: spawning, larval rearing and grow out. Few grouper farmers specialise in more than one area. Farmers in both study regions reported that Hybrid grouper were desirable due to the strong market demand and high sale prices, fast growth rate, and higher survival compared to other grouper crops. Farms had different economic characteristics between region and type, major differences were seen in the species cultured, number of people employed and age of farms. All farms interviewed generated annual net sales revenue exceeded the cost of goods sold. Earthen pond farms in Central Vietnam generated a median gross margin of US$ 8741 per year, Central region nurseries US$ 8059, and Northern Sea cage farms US$ 4562. Relative importance, calculated by contribution to total farm income, indicated that Hybrid grouper is the most important crop for grow out farms in both regions and second most important for nursery farms. Central region grow out farms generate higher gross margins than Northern Sea cage farms, which is a result of Central region grouper growing faster, having higher survival rates, and selling for more per kg than those grown out in the Northern region. The main changes to the industry since 2010 have been the introduction of Hybrid grouper as a new crop, the increase in average grouper sale price, and the move to full life-cycle aquaculture. Average sale price for grouper has increased from US$ 7.7–9.6/kg (adjusted to 2019 US$) to US$ 9–15/kg. The findings indicate that the most significant constraints to the growth and diversification of the grouper aquaculture industry in Vietnam are the limited availability of Hybrid fingerlings due to difficulties in larval rearing, and increases in feed costs due to a lack of domestic feed suppliers. Notwithstanding these constraints, the higher gross margins of Hybrid grouper relative to other financially viable grouper crops suggests continued, albeit moderated, growth of grouper aquaculture in Vietnam.