While Wikipedia is a subje ct of great interest in the com- puting literature , very little work has considered Wikipedia’s important relationships with other information technologies like search engines. In this paper, we report the results of two deception studies whose goal was to b etter understand the critical relationship between Wikipedia and Google. These studies silently removed Wikipedia content from Google search results and examined the effect of doing so on participants’ interactions with both websites. Our findings demonstrate and characterize an extensive interdependence between Wikipedia and Google . Google becomes a worse search en- gine for many queries when it cannot surface Wikipedia con- tent (e.g. click - thro ugh rates on results pages drop signifi- cantly) and the i mportance of Wikipedia content is likely greater than many improvements to search algorithms . Our results also highlight Google’ s critical role in providing read- ership to Wikipedia . However, we also fo und evidence that this mutually benefic ial relationship is in jeopardy: changes Google has made to its search results that involve directly surfacing Wikipedia content are significantly reducing traffic to Wikipedia . Overall, our findings argue that researchers and practitioners should give deeper consideratio n to the interde- pendence between peer production communities and the in- formation technologies tha t use and surface their content.