This paper describes the validation of a self-evaluation instrument for teachers in secondary education to solicit feedback from their pupils regarding specific aspects of the teacher's practice in class. This 92-item instrument--Teachers Learn from Pupils-Secondary Education (TLP-SE)--assesses 10 relevant classroom environment dimensions: effective learning time, structured instruction, monitoring pupil's progress, feedback, high expectations, reinforcement, work climate in class, promoting self-reliance, harmonic personality development, and recognizing autonomy. A sample of 1140 secondary education pupils (c.q. 69 classes) from Belgium-Flanders responded to TLP-SE. The instrument could be of interest for the larger community of teachers in secondary education since it combines teacher self-evaluation and pupil participation. Moreover, separate analyses of unidimensionality, validity, and reliability provide evidence of the sound psychometric properties of this self-evaluation instrument. (Contains 6 tables and 2 figures.)