This paper explores the incidence and trends of open innovation practices among small- and medium-sized enterprises (SMEs) in the Netherlands, focusing on the motives and perceived challenges associated with these practices. Drawing from a survey of 605 innovative SMEs, the study finds that SMEs engage in various open innovation practices, including customer involvement, external networking, and employee involvement, and have increasingly adopted such practices over the past 7 years. There are no significant differences between manufacturing and service industries, but medium-sized firms are more heavily involved in open innovation than smaller firms. SMEs primarily pursue open innovation for market-related motives, such as meeting customer demands and keeping up with competitors. The most significant challenges they face relate to organizational and cultural issues, particularly in dealing with increased external contacts. The study concludes that open innovation is not only relevant for high-tech multinational enterprises but also for a broader range of firms, including SMEs, and that it is becoming increasingly adopted by these enterprises.This paper explores the incidence and trends of open innovation practices among small- and medium-sized enterprises (SMEs) in the Netherlands, focusing on the motives and perceived challenges associated with these practices. Drawing from a survey of 605 innovative SMEs, the study finds that SMEs engage in various open innovation practices, including customer involvement, external networking, and employee involvement, and have increasingly adopted such practices over the past 7 years. There are no significant differences between manufacturing and service industries, but medium-sized firms are more heavily involved in open innovation than smaller firms. SMEs primarily pursue open innovation for market-related motives, such as meeting customer demands and keeping up with competitors. The most significant challenges they face relate to organizational and cultural issues, particularly in dealing with increased external contacts. The study concludes that open innovation is not only relevant for high-tech multinational enterprises but also for a broader range of firms, including SMEs, and that it is becoming increasingly adopted by these enterprises.