The role of outdoor advertising in achieving marketing growth in the telecommunication industry – case study of selected telecommunication institutions in Nigeria. This topic, the role of outdoor advertising in achieving marketing growth in the telecommunication industry in Imo state was conducted to investigate the extent of the relationship between advertising and the marketing growth of telecommunication institutions. However, to achieve the goal of the study, the quasi-experimental research design was used to study three (3) telecommunication firms, where twenty three questionnaires were administered to the respondents in order to obtain firms’ timely information. After a critical analysis of the data collected, the hypothesis was tested using the analysis of variance (ANOVA) with the aid of statistical product and services solution package (spss) and the following were the findings that outdoor advertising contributes significantly to the marketing growth of telecommunication firms and moderating factors interfere with the relationship between outdoor advertising and marketing growth in the telecommunication industry. Based on the findings, the following were recommended: the telecommunication industry should improve on its outdoor advertising strategy to make it very effective and efficient. The telecommunication industry should ensure the conduct of customer analysis regularly so as to ensure a better understanding of their target audience. Firms in the telecommunication sector should higher qualified professional agencies to enhance the effectiveness of their advert. They should endeavor to adopt a media that is versatile flexible and with wide coverage so that they can effectively reach a larger size of the target market. They should effectively carry out the environmental assignment to enable them to know about current opportunities and threat that might affect the effectiveness of their outdoor advertising strategies.