This paper identifies both the breadth and the depth as two crucialdimensions of user interaction from an ecosystem viewpoint. Wepostulate that the breadth and the depth of user interaction arecritical to the number of new products developed anddevelopment speed, which can then lead to new venture growth. Survey data from 341 new ventures from ICT sector illustrates thatthe number of new products developed mediates therelationships between user interaction breadth, user interactiondepth and new venture growth, and development speedmediates the influence of user interaction depth on new venturegrowth. This study contributes to the literature by refining theconceptualization of user interaction, and developing atheoretically grounded research model to investigate therelationships among user interaction, new product developmentand new venture growth.