AbstractSocial media has become an increasingly important tool for parties to set issues on the political agenda. However, its rapid rise raises questions about the role of traditional venues such as parliaments. This study hypothesizes that parties strategically choose to initiate issues in parliamentary debates instead of on social media to establish dominance through real‐time discussions. Consequently, only after these issues are introduced and debated in parliament do parties use digital platforms like social media to reinforce them on the political agenda. Analyzing over 430,000 parliamentary speeches and 240,000 Facebook posts by parties in Australia, Belgium, Canada, Croatia, and the UK, from 2010 to 2022, the study reveals that issues discussed in parliamentary debates—primarily those raised by opposition parties—typically do not initially emerge on social media but only attract online attention after being introduced in parliament. These findings offer new insights into the strategic decisions of parties in agenda‐setting.