This study aimed to figure out the types of illocutionary acts produced by a lecturer in online classroom interaction and the functions of the illocutionary acts. This research applied a descriptive qualitative design by involving a lecturer of the English Language Department of Lambung Mangkurat University. The data was collected by using an observation sheet, interview guide, and recording which was analyzed following the steps namely data reduction and data display. The result showed that the lecturer produced four kinds of illocutionary acts in online classroom interaction. There were 275 utterances of illocutionary acts conveyed by the lecturer during the teaching and learning comprising of 165 directive data, 86 expressive data, 23 representative data, and 1 commissive data. Moreover, the findings showed that there were three kinds of illocutionary functions based on 250 data collected. They are 161 competitive data, 86 convivial data, and 3 collaborative data. The lecturer also used questions in the teaching and learning process to engage students in the discussion and assist the lecturer in assessing the students' knowledge on the lesson materials. This finding implies that further research is needed by expanding the focus of speech acts to obtain more comprehensive data about speech acts in online classroom interaction.