The study investigate the relationship between organisational communication systems and administrative efficiency at federal tertiary institutions in Bayelsa State. Cross-sectional survey research design was adopted. The populations for this study involve administrative personnel in Bayelsa State make up the study population. The study sample size of the study was determined using the Taro Yamane (1967) formula, which gave birth to a sample size of 187. Questionnaire used as instrument for primary data collection. Descriptive and inferential statistics were employed to accomplish this. Means, percentages, and frequencies were computed as part of the descriptive analysis. Using SPSS, Spearman Rank Order Correlation Coefficient test to look for correlations between our variables. The findings revealed that although there was no notable correlation between the dimensions and measurements of the research as a whole, horizontal, and diagonal communication each exhibited a substantial correlation with both administrative efficiency. The study indicates that there is a strong empirical link between organisational communication systems and administrative efficiency in these institutions. The study therefore recommend that it is necessary to have a policy that enables unrestricted contact among all staff members, irrespective of their hierarchical position or organisational level. Diagonal communication of this nature would expedite the process of making timely decisions to resolve issues inside the organization.