Herein we explore whether the social psychology theory of commitment via a truth-telling oath can reduce coordination failure. Using a classic sequential coordination game, we ask all players to sign voluntarily a truth-telling oath before playing the game with cheap-talk communication. Three results emerge with commitment-via-the-oath: (1) coordination increased by nearly 50 percent; (2) senders' messages were significantly more truthful and actions more efficient, and (3) receivers' trust of messages increased.