Models of communication simplify or represent the process of communication. Most communication models try to describe both verbal and non-verbal communication and often understand it as an exchange of messages. Their function is to give a compact overview of the complex process of communication. This helps researchers formulate hypotheses, apply communication-related concepts to real-world cases, and test predictions. Despite their usefulness, many models are criticized based on the claim that they are too simple because they leave out essential aspects. The components and their interactions are usually presented in the form of a diagram. Some basic components and interactions reappear in many of the models. They include the idea that a sender encodes information in the form of a message and sends it to a receiver through a channel. The receiver needs to decode the message to understand the initial idea and provides some form of feedback. In both cases, noise may interfere and distort the message.

Models of communication are classified depending on their intended applications and on how they conceptualize the process. General models apply to all forms of communication while specialized models restrict themselves to specific forms, like mass communication. Linear transmission models understand communication as a one-way process in which a sender transmits an idea to a receiver. Interaction models include a feedback loop through which the receiver responds after getting the message. Transaction models see sending and responding as simultaneous activities. They hold that meaning is created in this process and does not exist prior to it. Constitutive and constructionist models stress that communication is a basic phenomenon responsible for how people understand and experience reality. Interpersonal models describe communicative exchanges with other people. They contrast with intrapersonal models, which discuss communication with oneself. Models of non-human communication describe communication among other species. Further types include encoding-decoding models, hypodermic models, and relational models.

The problem of communication was already discussed in Ancient Greece but the field of communication studies only developed into a separate research discipline in the middle of the 20th century. All early models were linear transmission models, like Lasswell's model, the Shannon–Weaver model, Gerbner's model, and Berlo's model. For many purposes, they were later replaced by interaction models, like Schramm's model. Beginning in the 1970s, transactional models of communication, like Barnlund's model, were proposed to overcome the limitations of interaction models. They constitute the origin of further developments in the form of constitutive models.

Models of communication are representations of the process of communication. They try to provide a simple explanation of the process by highlighting its most basic characteristics and components. As simplified pictures, they only present the aspects that, according to the model's designer, are most central to communication. Communication can be defined as the transmission of ideas. General models of communication try to describe all of its forms, including verbal and non-verbal communication as well as visual, auditory, and olfactory forms. In the widest sense, communication is not restricted to humans but happens also among animals and between species. However, models of communication normally focus on human communication as the paradigmatic form. They usually involve some type of interaction between two or more parties in which messages are exchanged. The process as a whole is very complex, which is why models of communication only present the most salient features by showing how the main components operate and interact. They usually do so in the form of a simplified visualization and ignore some aspects for the sake of simplicity.

Some theorists, like Paul Cobley and Peter J. Schulz, distinguish models of communication from theories of communication. This is based on the idea that theories of communication try to provide a more abstract conceptual framework that is strong enough to accurately represent the underlying reality despite its complexity. Communication theorist Robert Craig sees the difference in the fact that models primarily represent communication while theories additionally explain it. According to Frank Dance, there is no one fully comprehensive model of communication since each one highlights only certain aspects and distorts others. For this reason, he suggests that a family of different models should be adopted.

Models of communication serve various functions. Their simplified presentation helps students and researchers identify the main steps of communication and apply communication-related concepts to real-world cases. The unified picture they provide makes it easier to describe and explain the observed phenomena. Models of communication can guide the formulation of hypotheses and predictions about how communicative processes will unfold and show how these processes can be measured. One of their goals is to show how to improve communication, for example, by avoiding distortions through noise or by discovering how societal and economic factors affect the quality of communication.

Many basic concepts reappear in the different models, like "sender", "receiver", "message", "channel", "signal", "encoding", "decoding", "noise", "feedback", and "context". Their exact meanings vary slightly from model to model and sometimes different terms are used for the same ideas. Simple models only rely on a few of these concepts while more complex models include many of them.

The sender is responsible for creating the message and sending it to the receiver. Some theorists use the terms source and destination instead. The message itself can be verbal or non-verbal and contains some form of information. The process of encoding translates the message into a signal that can be conveyed using a channel. The channel is the sensory route on which the signal travels. For example, expressing one's thoughts in a speech encodes them as sounds, which are transmitted using air as a channel. Decoding is the reverse process of encoding: it happens when the signal is translated back into a message.