English has two major future tense constructions, will and be going to. Additionally, English can also use the present tense with a future-marking adverbial to express futurity. However, the distributions of these future markers are not free but limited. Instead of discriminating the differences among these distributions through direct comparison to etymological meanings or intuitive examples, this study offers an account for the semantic and syntactic differences between the two major English future tense constructions by analyzing data retrieved from the British National Corpus (BNC). The focus of attention is chiefly on the semantic and syntactic differences that lead to the choices British English native speakers make when expressing futurity. Based on the empirical analysis of data from the BNC, this study demonstrates that distribution of the future tense constructions seems sensitive to the following factors: (1) event-time orientation (temporal posteriority) or present-time orientation (prospective aspect), (2) the levels of verbal dynamicity in the whole sentence, (3) contexts of subordination, and (4) different text categories. The analysis suggests that the futurity constructions are not in the same distribution but are semantically and syntactically different. Utilizing its findings, this study aims to enhance second language learners’ expression of futurity by providing pedagogical suggestions.