Decisions formed from a diversity of opinions usually lead to better long-term outcomes. So, when you believe that your team or organization is missing something important, moving in the wrong direction, or taking too much risk, you need to speak up. Done effectively, dissent challenges groupthink, reminds those in the majority that there are alternatives paths, and prompts everyone to get creative about solutions. Six decades of scientific research point to strategies those without formal power can use to make sure their dissenting ideas are heard. First, pass the in-group test by showing how you fit in. Then pass the group threat test by showing how you have your team’s best interest at heart. Make sure your message is consistent but creative tailored for different people, lean on objective information, address obstacles and risks, and encourage collaboration. Finally, make sure to get support. Dissent isn’t easy but it can be extremely worthwhile.