In mobile ad hoc networks (MANETs), each node should not only work for itself, but should be cooperative with other nodes. Under such environment, some nodes may misbehave for individual interests. Currently two categories of trust management frameworks, reputation-based framework and trust establishment framework, are used to guarantee nodes to perform normal behavior. However, in reputation-based framework, it is unreasonable that only one parameter, trust value, is considered. Meanwhile, the trust establishment framework is vulnerable under the selective misbehavior attack, by which the attacker performs different behaviors to different nodes. To solve these problems, we propose an objective trust management framework (OTMF) for MANETs, by which one node evaluates the trustworthiness of another node objectively based not only on direct observations, but on second-hand information. To compare the OTMF with the existing frameworks, we provide performance evaluation. The evaluation results show that the OTMF can obtain more reliable trust than the reputation-based framework and can prevent the selective misbehavior attack more effectively than the trust establishment framework.