The purpose of the study was to investigate trade unionism and organizational effectiveness (a study of Nestle Nigeria plc), Lagos. The study adopted the descriptive survey research design with the following objectives; to assess the priority accorded welfare of employees in public organisations; to determine how employees are carried along in policy review and implementation with respect to communication; to evaluate the extent to which quality of negotiation influences employees performance and to appraise the extent to which management-employees relations influences productivity in the organisation. The study comprised one hundred and twenty (120) respondents randomly selected across the sample. A self- constructed questionnaire was used for data collection for the study. The questionnaire consisted of twenty (20) items on a 4 point. Likert scale tagged Trade unionism and organizational effectiveness (TUAOE).The statistical method used for the analysis of data was simple percentage and chi-square. The hypotheses were tested at 0.05 level of significance. The findings of the study revealed that there is relationship between trade union and provision of welfare measures among workers in an organization, that trade union enhances participation of workers in the management affair of the organization, that trade union ensures the reduction of disputes and sue for dialogue and that management-employees relation promote the organizational productivity. The study therefore concluded and recommended that the welfare of employees should be considered, top-down communication in the organization should be smoothened, quality of negotiation and employees performance should be encouraged and that employee should be made to partake in critical decision so as to have a sense of belonging.