Psychologist Carol Dweck distinguishes fixed and growth mindset based on people's belief that intelligence is fixed or malleable, respectively. Conducted studies show that fostering growth mindset can improve student's motivation and educational achievement. One of the main ways in which teachers can encourage the growth mindset is a way of giving feedback. The purpose of the current study is to assess the level of teachers´ mindset according to the Mindset theory and detect whether teachers mindset is related to the way of giving feedback, particularly in response to flawless and fast student performance. Dweck Mindset Instrument (DMI) supplemented with additional questions was electronically administered to collect a set of data. The research group consisted of kindergarten, primary and secondary school teachers (N = 175). The results show that teachers most often responded to a flawless and fast performance of a pupil with a generally positive assessment, positive assessment of abilities, reactions in the spirit of growth mindset, keeping pace with other students, describing or asking questions. No relationship was found between the mindset of teachers and the way they respond to the pupil's flawless and fast performance.