Mainstream-school teachers are the most important assets for students with special educational needs (or diverse conditions) who hope to achieve real inclusion. However, teaching experience, attitudes, and knowledge can either promote or hinder efforts towards inclusion. A cross-cultural study was conducted to examine perceptions, knowledge, and attitudes towards inclusion in teachers from Ghana, Germany, and Spain, about intervention with special-education students enrolled in their classrooms. The participants comprised 363 teachers -- 156 men (43%) and 207 women (57%) -- from three countries (Ghana, Germany, and Spain). Of the teachers, 150 (41.3%) were from Ghana, 62 (17.1%) were from Germany, and 151 (41.6%) were from Spain. The results showed that there were significant differences in teachers' self-confidence and in the amount of personal and material resources they received from administrators and schools. In general, the Spanish teachers reported lower levels for these variables. All the teachers showed adequate levels of knowledge about instructional strategies and students' characteristics, although those from Ghana demonstrated significantly more knowledge than the others about students' characteristics. Finally, the teachers differed by country in terms of their attitudes towards inclusion, with the teachers from Spain and Germany demonstrating slightly better attitudes. They all agreed on the need for additional training as a key aspect in this regard.