Methods, apparatus, systems and articles of manufacture are disclosed to identify co-relationships between media using social media. An example apparatus includes an audience estimator to: estimate a first audience of first media based on a first set of media-exposure social media messages corresponding to client devices referencing the first media, and estimate a second audience of second media based on a second set of media-exposure social media messages corresponding to the client devices referencing the second media. The example apparatus also includes a pairing classifier to: determine a pairing-score for a media-pairing based on the first and second audiences and the first and second sets of media-exposure social media messages, determine a relationship threshold to apply to the media-pairing based on the first media and the second media, and classify the media-pairing based on the pairing-score and the relationship threshold to improve an accuracy of a system associated with generating audience analysis information.