Marketing plays a key role in increasing the popularity of e-cigarettes. We conducted a systematic review of the existing literature published between 2003 and 2019 in eight databases to describe e-cigarette marketing communication messages by communication channels and marketing communication strategies. Forty-one articles were included in the analysis after screening. Ten key messages were identified. Cessation and health-related benefits (each n = 31, 75.6%) were the most reported marketing communication messages, followed by sociability/lifestyle and use experience. The Internet (n = 35, 85.4%) was the most studied communication channel compared to print, TV/movie/radio, and point-of-sales (POS)/retail stores. The most studied marketing communication strategies were advertising (n = 34, 82.9%), followed by public relations and sales promotion. Published research studies reported consistent messages about e-cigarettes across communication channels and marketing communication strategies. Claims of smoking cessation and health-related benefits were widely identified in the existing literature. While therapeutic claims are prohibited, soft sell messages, such as social appeals, for which regulatory reach may be limited, may require educational campaigns. Internet marketing has attracted much attention, with limited studies on messages in print, TV/movie/radio, and POS/retail stores. The lack of studies of direct marketing messaging indicates a big gap between industry spending and academic research; more studies of messaging utilizing this strategy are needed.