A contest sponsor or crowdsourcing intermediary hosting an open innovation contest can employ knowledge-sharing activities such as panels, meetings, or even community forums to help maximize each contestant’s performance. However, in addition to the paradox of openness resulting from the incentive to protect their knowledge assets, contestants face a predicament related to sharing, as benevolently helping others may reduce their opportunity to win the contest. In this research, we integrate two stylized models to determine how a contest sponsor can most efficiently deploy its resources under budget constraints, and explore how to stimulate co-creation in knowledge-sharing activities. Our findings indicate that employing educational workshops to encourage brainstorming among contestants before submitting their work results may be inefficient if the prize is too high. In addition, if a contest sponsor values the overall contribution made by contestants, encouraging knowledge-sharing behavior can benefit the intermediary in a crowdsourcing-based open innovation contest when the number of contestants and the contest sponsor’s budget are set appropriately.