Based on the Technology Acceptance Model (TAM), the aims of the present cross-sectional study were i) to investigate acceptance by teachers of an open-source, collaborative, free m-learning app, named "Artefac," ii) to examine whether teachers' self-approach goals (i.e., the motivation to teach more effectively than before) may be a relevant external variable to include in the TAM, and iii) to investigate potential differences of acceptance between school subjects (humanities and social science teachers vs. science teachers), status (in-service teachers vs. pre-service teachers), and contexts (teachers in schools classified as difficult vs. teachers in schools not so classified). A total of 419 French teachers (277 women, 142 men) took part in the present correlational survey. After reading a text with pictures presenting an open-source, collaborative, free m-learning app, named "Artefac," the participants filled out a self-reported questionnaire about its acceptance before use, assessing perceived usefulness for teaching, perceived ease of use, perceived enjoyment, and intention to use. Teachers' self-approach goals were also assessed. One-sample t-tests and structural equation modeling were used to analyze the data. The results showed that Artefac was rather well accepted by teachers (with middle to strong effect sizes), whatever their school subject, their status, and their teaching context. The results also highlighted that teachers' self-approach goals positively predicted perceived enjoyment and perceived ease of use but did not predict perceived usefulness for teaching, indicating that the more teachers wanted to increase their teaching skills, the more they found "Artefac" easy to use and fun to use.