Educational robots, as a recent addition to educational technology, have been widely examined, researched, and gradually implemented in educational processes worldwide. Being used as the educational tool they have most commonly been used as a part of STEM subjects (Eguchi, 2014). While preparing lessons that include robot usage, several authors (e.g., Bers et al., 2002; Alimisis, 2013; Eteokleous & Ktoridou, 2014) suggest they should be created and developed as a lesson based on a constructivist approach. This means that the students should be the main constructors of the lesson, who create, research, develop, discuss, and present everything they are dealing with, and the teachers should be the ones who guide them through the process and help them or provide some suggestions if needed. This type of lesson is lately advised to be used with 21st-century students (Matijević, 2016; 2017) since they have been surrounded by digital technology their whole lives and are eager to work on their own and construct their knowledge using acquired skills and knowledge. In recent years, the researchers expanded robot usage to language learning subjects (Randall, 2019), which consequently established the term robot-assisted language learning - RALL (Han, 2010; 2012). When it comes to RALL, it is usually applied in teaching English as a foreign language. Teaching English includes topics from various fields, enables the teacher the usage of different teaching methods, and integration of versatile instructional materials. Therefore, students prefer the English language as a subject (Mihaljević Djigunović, 2012b) and express positive attitudes towards it (Mihaljević Djigunović, 2007). In the Croatian environment, educational robotics is still mainly put into practice with extracurricular activities in the matter of workshops and competitions. As it is shown that the students are interested in using and have accepted educational robotics in their spare time, it is assumed they would favour its usage in their formal education. Thus, it is important to evaluate its effects on its implementation, which can someday lead to educational robotics being part of the curriculum. Bearing in mind the benefits of the English language as a subject and students’ positive outlooks towards it, the implementation of a robot into the mentioned subject and evaluating its effect should be a good starting point for any further examination and development. The evaluated effects are part of the cognitive, behavioral, and affective domains. In terms of the cognitive domain, the change in students’ learning outcomes needs to be researched. When it comes to th behavioral domain, the focus will be on students’ collaboration, participation, and engagement. Lastly, the affective domain will include students’ motivation and attitudes toward robot usage. The examination of motivation will be based on the ARCS model (attention, relevance, confidence, satisfaction) (Keller, 2010), which proved to be effective in previous similar research that included the implementation of a robot in the English as a foreign language classroom (Chin et al., 2014; Hong et al., 2016). Consequently, this research aims to investigate the aspects of primary school learning of the English language in which the use of robots is effective and to examine the motivation of students in using teaching materials in learning English as a foreign language and their attitudes towards such learning. It is believed that the students who use robots will be more motivated, in comparison to the ones who have used some other materials, in every aspect of the ARCS model. It is also believed that there will be no difference in learning outcomes between the two mentioned groups. The students who will use robots will be more positive, open-minded, collaborative, and engaged during the lesson. They will also show preferences towards robots, will be interested in using them again, and will imagine new ideas about how to use them and which features should be included.This research has been prepared as quasi-experimental research. It included fourth graders (N = 219) from seven primary schools in Zagreb, Croatia, who were separated into two groups -the experimental and control group. The research lasted for three weeks and was conducted on three English language lessons (one lesson per week). The lessons included topics on British culture, and each week during one activity, students from the experimental group used one of the robots (STEMI Hexapod, Cubelets Robot Blocks, Thymio) as the instructional material. The control group, who was not under the treatment, used some other instructional material instead of a robot. The research included a mixed-method approach. The instruments as a part of a quantitative research method were the instructional materials motivation questionnaire and the knowledge test. The students filled out both at two measurement points – before the intervention started and after the intervention finished. The instruments as a part of a qualitative research method were semi-structured interviews and observation. The semi-structured interview was carried out after the intervention with seven focus groups with randomly chosen participants of the experimental group. At the time of the intervention, 22 pre-service teachers joined the lessons as independent observers, who observed the lessons based on the observational sheets.The results showed a decrease in motivation in both groups after the treatment. There was no significant difference in the aspects of relevance, confidence, and satisfaction, but there was a significant difference in the aspect of attention. The main reason for it was the functions of the robots and their characteristics, which did not always work properly. When it comes to learning outcomes, the results have shown that there was no significant difference between the groups, as was expected. Even though the robots were not functioning the best, the students were very excited to use them, they wanted to use them with their peers, they were engaged in a lesson, and were willing to participate the whole time. They expressed all kinds of positive emotions (happiness, excitement, curiosity) and an interest in using the robots again. They see the robot as an effective tool, think it contributes to the lesson, and are satisfied with how they have used it. The results have also shown that nothing would be possible and effective if it was not for the contribution of the teachers. The teacher who was well-prepared, helpful, enthusiastic, and approachable, who carried the lessons according to the lesson plans, who equally included every student in the lesson, and who was interested and willing to use the robots, contributed to the lesson's effectiveness, and most importantly, the effectiveness of the robot usage. Even though the teacher was not the focus of the lesson, without the teacher’s contribution, the robot as the educational material would not have achieved its potential. To conclude, the robot as the educational material had the most impact on students’ collaboration, teamwork, and engagement during the lesson. Robot usage created a positive working atmosphere where everyone was involved and willing to contribute to the lesson equally. It brought positive emotions out of the students that lead to satisfaction with robot usage and affirmative attitudes toward implementing educational robots into English as a foreign language classroom. It has negatively contributed to the students’ motivation for instructional materials usage, which was probably due to technical problems that occurred. As expected, the robot had no influence on achieving the educational outcomes, which means that educational outcomes can be evenly achieved with any educational material. Thus, it has been shown that the manner of using the material is more important than the material itself. If a teacher develops a lesson appropriately, where the student is the one who works on developing and building knowledge with the usage of already acquired skills and in collaboration with others, in other words, according to the constructivist approach, the implementation of a robot as the educational material into lessons of the English language will be efficient and convenient. Therefore, the mentioned findings can serve as an onset for further development of this new, appealing, and complex material, which should be thoroughly empirically researched with other stakeholders of the educational system.