As online news today is an important source of political information and available in vast quantities, understanding its use and its impact on citizens’ political knowledge is vital. The aim of the present study is to identify different usage patterns of online news and their relation to individually perceived (i.e., subjective) and actually measurable (i.e., objective) political knowledge. To do so, we conducted an online survey of German online news users (n = 396), investigating characteristics of their online news usage as well as their subjective and objective political knowledge. Latent class analysis revealed six distinct usage patterns, of which a usage pattern drawing heavily on social media and push accesses as a source of news (e.g., Facebook newsfeed, email newsletter) and being rather highly driven by entertainment needs has been found to be associated with an overestimation of one’s own political knowledge (illusion of knowing). The potential negative implications of such an illusion of knowing are discussed against the backdrop of the democratic ideal of informed citizens.