A public speech is considered a way in which a person communicates his/her message for multiple reasons, and one of them is to persuade. It influences people’s decisions and behaviours to act according to the intended purpose of the speaker. To accomplish this, one needs to use some techniques to maintain social relations, support and gain respect from the audience. One of these techniques is using polite language. Being polite has specific effects and can serve as a persuasive tool in speeches. This study analyses Martin Luther King’s speech “HOW LONG? NOT LONG” pragmatically following Brown and Levinson’s (P. Brown et al., 1987) politeness theory. It seeks to identify the politeness strategies used by the speaker to persuade the audience and highlight the most used ones. The analysis shows that four politeness strategies are used at different frequencies. The highly used strategy is positive politeness (226) since the speaker attempts to build intimacy and establish a close relationship with the audience. In contrast, the least frequent is negative politeness (12) because he does not want to strengthen the audience’s desire to be free of influence.