The newsworthiness of trans issues has increased over the last two decades, resulting in unprecedented media visibility of trans people. However, there is still a long way to go in the study of the Agenda Building factors that have influenced this media attention. The aim of this article is to analyze the Intermedia Agenda Setting (IAS) dynamics on the coverage of trans issues in the Spanish digital news media landscape during the period 2001–2020. A quantitative content analysis was conducted, using the Granger Causality test for both issue-salience and attribute-salience IAS dynamics between different types of news media. In general, news flows have been observed from national-to-local, from progressive-to-conservative, and from legacy-to-digital-native media at the issue-salience level. However, from 2016 onwards, progressive and conservative media influence one another. This can be attributed to the generation of an alternative agenda on trans issues by the anti-trans rights movement in recent years. As a consequence of the presence of these competing trans rights and anti-trans rights agendas, media coverage of trans issues has become polarized. In contrast, IAS dynamics at the attribute-salience level are not clear. These findings suggest IAS dynamics have played an essential role in the increasing media attention on trans people. However, the decline in the media delegitimization of trans rights cannot be attributed to IAS dynamics. This study highlights the dynamic nature of IAS, which can evolve based on the agenda and degree of eliteness of each media outlet at any given time.