Interoperability in the public sector can be improved by the use of open standards. Nonetheless, the openness of standards in government policies is debatable. This paper introduces the Dutch government policy on open standards, and will introduce a multi-dimensional view (and model) on openness rather than a one-dimensional strict definition. Applicability of the multi-dimensional model is tested in a case study, which demonstrates that this model has value for standardization organizations active in the government domain. In future cases the model helps in understanding how government-related standardization organizations can influence openness in a situation-specific way and the model therefore narrows the gap between open standards policy and practice.