During an armed conflict, the use of explosive weapons with wide area effects in populated areas has a devastating impact on civilians. Less visible than the direct effects of explosive weapons, but equally devastating, are the reverberating effects of the use of explosive weapons in populated areas. While there is growing consensus that parties to an armed conflict are legally obliged to take into account the reasonably foreseeable reverberating effects of an attack, particularly for the purposes of the rules on proportionality and precautions in attack, the precise scope of this obligation remains unclear. After setting out the legal arguments in support of the position that reasonably foreseeable reverberating effects must be taken into account, this article goes on to examine how such effects should be evaluated and how they must be avoided or minimized.