This study aims at investigating the effects of a teaching intervention, the design of which is informed by evidence from educational theories and research data, on students' images of scientists. A quasi-experimental design with a non-equivalent pre-test-post-test control group (CG) was used to compare the outcomes of the intervention. The subjects of the study were 63 grade 6 (aged 12 and 13) students who were in two different classes and taught by two different teachers. The study was undertaken in ten class hours over a 4-week period, during which the topics related to matter and heat concepts were covered as a part of the regular Turkish Science and Technology Curriculum. Before the intervention, there was no significant difference between the two classes in terms of their achievements in the Science and Technology course (t(63) = -0.943, p > 0.05). Accordingly, one of the classes was randomly selected as the experimental group (EG). A modified version of the Draw-a-Scientist Test, in conjunction with individual interviews, was used to assess students' images of scientists at the beginning and end of the study. The results showed that students who had followed evidence-informed instruction had significant gains from the pre-test to the post-test regarding their images of scientists compared to students with traditional instruction. Many students in the EG started to view scientists as realistic people rather than as extraordinary people or mythical creatures. Nevertheless, several students in the CG held images of scientists and their work which fit a stereotype of scientists as male, bald, bespectacled, wearing a laboratory coat, working alone in a laboratory environment and having a limited social life. Some possible implications for teaching and further research are discussed.