This study focuses on the role the customer plays in the adoption and consolidation of Agile practices in software development firms. We considered two main aspects: 1) the degree of collaboration between customers and suppliers; 2) the degree of active participation of the customer in software development processes. We argue that both these factors affect the level of Agility of an organization. To investigate this topic we conducted a survey among firms that use agile software development methodologies. The sample of respondents was obtained from the social network Linkedin. We received one hundred and five valid questionnaires before subjecting the data to hierarchical linear regression analysis. Our findings suggest that a collaborative and active role of the customer increases Agility. This study provides original empirical data on the frequency of use of Agile practices in software development processes. From a theoretical point of view it clarifies the role of two different customer-related factors: customer collaboration and customer participation.