Дослідження присвячено вивченню соціально-психологічних умов синхронного текстового діалогічного комп'ютерно-опосередкованого спілкування, що мають вплив на виникнення та підтримання взаєморозуміння між співрозмовниками. Побудовано концептуальну модель психологічних умов взаєморозуміння в інтернет-спілкуванні, в якій представлено мотиваційні, темпоральні, стилістичні і процесуальні умови, умови емоційного обміну, а також онлайн-активність особистості та визначено їхній соціально-психологічний зміст. Виявлені основні ознаки взаєморозуміння в синхронному діалогічному текстовому онлайн-спілкуванні Встановлено зв'язки між рівнем взаєморозуміння і характеристиками мотивації співрозмовників до онлайн-спілкування, досвідом користування інтернетом, комунікативної компетентністю та особливостями взаємодії з партнером по спілкуванню, а також різними аспектами онлайн-активності комунікантів – створенням і розповсюдженням творчих медіапродуктів, досвідом онлайн-комунікації, вибірковістю і критичністю споживання інформації у віртуальному просторі. Запропоновано тренінгову програму для підвищення взаєморозуміння в онлайн-спілкуванні молоді в інтернеті.^UThe research is devoted to the study of the socio-psychological conditions of synchronous textual dialogical computer-mediated communication that have an influence on the emergence and maintenance of mutual understanding between the interlocutors. The main groups of psychological conditions of mutual understanding in the Internet communication are identified and applied in the conceptual model (motivational, temporal, stylistic and procedural conditions, conditions of emotional exchange as well as personal online-activity).The concept of mutual understanding is investigated theoretically and empirically, and through the prism of the views of ordinary Internet users is defined as the ability of the interlocutors to listen and hear the views of each other, respond adequately to it, and eventually generate a common view in the process of communication.The main side characteristics of the existence of mutual understanding in the synchronous dialogical textual online communication are detected: belief that the task was fulfilled and the purpose of communication has been achieved; there is no desire to change anything in a created product; the feeling of completeness of the conversation; a pleasant impression of the process of communication and its outcome; a desire to continue communication with a partner; rather fast pace of conversation; lack of awareness of the flow of time; immersion in the process of communication; a feeling that the partner is attentive; high evaluation of knowledge of the partner and respect for him.It is determined that the time characteristics of an online conversation between two interlocutors are related to the impression of the participants of the conversation from this conversation and the evaluation of its results. In particular, the shorter average length of the pause between the replica of the communicant and the reaction from their interlocutor is due to a higher appreciation of the mutual understanding in the dialogue, the results of communication and a more pleasant impression of the content of dialogue and communication with the partner. Contrarywise, the feedback with the mutual understanding is inherent in the actions of the interlocutors where there are consciousness of talk time and time checking. A low level of mutual understanding is inherent in dialogues in which the interlocutors firstly seek to convince each other in their correctness, allow long pauses between replicas, have a limited time to discuss the desired topics, and have lower appreciation of each other's competence.Personal characteristics of the communicants – a broad outlook, sensitivity to the emotions of the interlocutor as well as their subjective positive attitude towards the competence and reliability of the interlocutors – are the conditions that promote mutual understanding in online communication. The high level of Internet activity of the person involved in the dialogic online communication contributes to a better mutual understanding, especially with regards to components related to the application of critical thinking and the experience of communication in the virtual space. Based on the characteristics of their motivation to online communication, the experience of using the computer and the Internet, communicative competence and the features of interaction with the communication partner, there are four types of online-communicators in social networks: "harmonious", "non-motivated", "migrants from off-line" and "self-confident".For the formation of personal qualities and communicative skills among students, a training program "Training of smart online-communication" was developed. It contains information and exercises that can be used in programs aimed at increasing media-literacy and communicative competence among students. Participation in the training contributes to the reduction in the number of negative emotions that participants experience during Internet communication due to the difficulty in perception of the personal image, behavior and emotions of the interlocutor and the content of their messages, which leads to false attempts to identify the reasons for misunderstanding between the partners, as well as the decreased effectiveness of communication. The development of skills and realization of practices, related to cognitive, creative, communicative and contact aspects of online activity, promotes mutual understanding in online dialogues. This communication is two-way, in a sense of gaining experience in effective online communication that is characterized by mutual understanding between the interlocutors, also contributes to increasing the online activity of the communicator.