ABSTRACT The purpose of this study is to examine the impact of eTwinning projects on teachers' digital pedagogical competencies, international professional interactions, and students' 21st-century skills based on teachers' views. The study was conducted using the descriptive survey model, one of the quantitative research methods. The sample of the study consists of 154 teachers working in Turkey who have experience in eTwinning projects. A 5-point Likert-type questionnaire developed by the researcher was used as the data collection tool. The data were analyzed using the SPSS software package; Cronbach Alpha reliability coefficient, descriptive statistics, Pearson correlation analysis, one-way analysis of variance (ANOVA), and multiple linear regression analysis were applied. The research findings showed that the scale was highly reliable (α = .90). It was determined that teachers' opinions about eTwinning projects were highly positive in all sub-dimensions. Correlation and regression analyses revealed that the use of Web 2.0 tools and international interaction are meaningful and strong predictors of students' 21st-century skills (R² = .56). The ANOVA results showed that teacher competencies did not differ significantly according to the duration of eTwinning experience. As a result, it has been concluded that eTwinning projects provide an effective learning environment that supports teachers' digital pedagogical development, strengthens international collaboration, and develops students' 21st-century skills. Keywords: eTwinning, Digital Transformation, Web 2 Tools, Teacher Competencies, 21st-Century Skills, International Education.