Privatization varies considerably among local governments. One of the oft-listed explanations is the ability of public employees to block privatization. However, many studies on the influence of public employees on privatization do not use very precise measures of the influence of public employees, they have been unable to isolate a one-way effect, and the studies have not been attentive to whether the effect varies for different market forms. In this article, we focus on privatization in Denmark through a voucher market without price competition for eldercare services. Using new data for all 98 Danish municipalities in 2012, we are able to measure the strength of the public eldercare union as well as the number of the public eldercare workers relative to the number of local voters. We find that the increased union strength measured in terms of union density at the municipal level leads to substantially and significantly less privatization through the voucher market. By comparison, the estimated relationship between the relative number of public workers and privatization does not reach statistical significance. Features of the voucher market and qualitative evidence suggest that the union influence primarily goes through a direct user channel, that is through union influence directed at the service users, whereas a minor effect possibly runs through a political channel, that is lobbying directed at the local politicians.