This study investigates how six writing-instructions aimed at third-year students in upper secondary school, resulting in high student performance, are designed. The aim was to identify common patterns of speech acts and text activities in the writing-instructions and to examine how clearly these communicate what is expected of students. To address this, a qualitative analysis of the six writing-instructions was conducted using tools from systemic-functional grammar: speech act and the concept of text activity. The analysis results show that the writinginstructions primarily communicate through the speech acts of statement and command. The speech act statement is used to provide information about the requirements and expectations of the task, while the speech act command structures the instructional part. The congruent use of speech acts demonstrates that all writing-instructions clearly convey their message. The framing text activity of explanation is used in all writing-instructions, providing a clear guidance, and writing frameworks, and is clarified and reinforced by the embedded text activity of description. The study results suggest that writing-instructions that clearly communicate expected content, structure, and writing frameworks correlate with higher student performance. Further research could expand this study with either a larger sample or in combination with an interview study.