In this research, we investigate the relationship between television advertising and online word-of-mouth (WOM) by examining the joint consumption of television programming and production of social media by television viewers, termed social TV. We explore how television advertising impacts the volume of online WOM about advertised brands and about the programs in which the advertisements air. We also examine what encourages or discourages viewers to engage in this particular social TV activity. Using data containing television advertising instances and the volume of minute-by-minute social media mentions, our analyses reveal that television advertising impacts the volume of online WOM for both the brand advertised and the program in which the advertisement airs. We additionally find that the programs that receive the most online WOM are not necessarily the best programs for advertisers interested in online engagement for their brands. Finally, our results highlight the brand, advertisement, and program characteristics that can encourage or discourage social TV activity. We discuss the implications of our findings for media planning strategies and advertisement design strategies. Data, as supplemental material, are available at http://dx.doi.org/10.1287/mksc.2016.1002 .