During times of crisis when economic uncertainty is rampant, sound policymaking is paramount for a benevolent government that wishes to maximise social welfare; communication, in particular, becomes a powerful tool through which a government could guide society by affecting individuals’ beliefs. As people from different cultural backgrounds differ in what they find salient and how they respond to contextual cues, communication must be carefully tailored to a society’s cultural strength and diversity in order to achieve the desired outcome. This is not well-understood in the theoretical literature. Using an information design approach, I investigate how a benevolent government with commitment power optimally communicates with a society in which there is a continuum of players, potentially belonging to different groups. Players are randomly pairwise-matched and play a coordination game with multiple equilibria; crucially, their strategic behaviour is driven by societal culture and diversity via a process of introspection à la Kets and Sandroni (2021), which endogenises equilibrium selection. In the baseline model without diversity, I find that the government’s concavified payoff function under optimal communication is piece-wise and non-monotone in cultural strength; this non-linearity arises from conflicting coordination and persuasion effects. This model has possible applications to explaining cross-country differences in government communication during the Covid-19 pandemic and populism, and can generate empirically testable predictions.