The article deals with the assessment of school subjects in the framework of a multilingual learning environment. The authors analyze the features of assessing student performance in the context of subject-language integrated lessons, depending on their type. The importance of determining the purpose for which the assessment is carried out, as well as criteria for learning outcomes, communication skills is noted. Summative and formative types of assessment for integrated lessons are described, when the subject is assessed in a foreign language, samples of criteria are presented using the statements “can do”. The importance of feedback, building a dialogue with students about their successes and achievements, the need to teach students self-assessment is noted.