In Croatian legislation, it is prescribed that both trade unions and workers' councils protect the interests and rights of workers. As a result, it is clear that there is a certain similarity and mutual cooperation between them, but this does not in any case mean that there are no differences between trade unions and workers' councils, on the contrary. As an association of workers, a specific trade union protects the interests and rights of workers of its members, regardless of where these workers are employed. In contrast, the workers' council, as a body elected in accordance with the law by workers employed by a specific employer, protects the rights and interests of only those workers employed by that employer. In this regard, this paper systematizes the powers and obligations of trade unions and works councils in protecting the interests and rights of workers, which are established by the laws and other regulations of the Republic of Croatia. Accordingly, the paper points out the similarities and differences that exist in this context between trade unions and works councils. At a time of great job insecurity, as well as workers' wages in the Republic of Croatia, the role and comprehensive cooperative action of trade unions and workers' councils is of indisputable importance for workers. Therefore, it is logical that numerous legal norms have been incorporated into Croatian labor law regulations that regulate the activities of unions and works councils mentioned above in the protection of the rights and interests of workers. Unlike the trade union, which has the legally established right to trade union negotiations with the employer and thus has the possibility of achieving better working conditions for workers, the works council cannot participate in negotiations with the employer, but it has the right to receive appropriate notifications from the employer, to consult with by the employer and on joint decision-making with the employer in cases and in the manner prescribed by law. Through the synergy of action, the trade union and the workers' council can certainly significantly contribute to the protection of the interests and rights of Croatian workers.