Past earthquakes worldwide have demonstrated without doubt that extensive bridge collapses are caused during earthquake due to unseating or dislodgement of spans. This has led to improvement in the seismic design codes for bridges in the recent past where codes now highlight the necessity of implementing effective unseating prevention measures. Current practice worldwide is to resort to passive unseating prevention measures for highway bridges against earthquakes, which primarily include minimum support length requirements and use of unseating prevention restrainers. Important aspects of these strategies in terms of their effectiveness, limitations, and future research needs in various national and international codes are summarized and discussed in this paper.