Informal workplace learning (IWL) is an important part of workrelated continuing education, especially in the case of bluecollar workers. The current article presents a new measure of IWL, which we developed based on the already existing Dynamic Model of Informal Learning by Tannenbaum et al. (2010). We extended the model to eight components by theoretical considerations, introducing a second-order structure. Each component is represented on the IWL scale with three items, the subscales have sound internal consistencies (α range between .76 and .92). The article also presents a short version of the scale comprising eight items (α = .79). Study 1 describes the process of item selection, while Study 2 deals with different theoretically conceivable models comparing their model fits. The predicted model with eight factors in a second-order structure achieves the best model fit. In addition, convergent, discriminant, and criterion validity are demonstrated. Mediumsized relationships of IWL components to conscientiousness and learning outcomes confirm the nomological network we developed previously in our study. The discussion provides limitations and possible scientific and practical applications of the IWL scale, for example, the transfer of the measure to other contexts and target groups. K E Y W O R D S blue-collar workers, informal workplace learning, scale development