The role of the left angular gyrus (AG) in language processing remains unclear. In this study, we used transcranial magnetic stimulation (TMS) to test the hypothesis that the left AG causally supports the processes necessary for context-dependent integration and encoding of information during language processing. We applied online TMS over the left AG to disrupt the online context-dependent integration during a language reading task, specifically while human participants integrated information between two sequentially-presented paragraphs of text (“context” and “target” paragraphs). We assessed the effect of TMS on the left AG by asking participants to retrieve integrated contextual information when given the target condition as cue in a successive memory task. TMS applied over the left AG during the reading task impaired subsequent retrieval of integrated context-target information in the memory task. These results provide the first evidence of a causal link between the left AG function, online information integration and associative encoding during language processing.