Penelitian ini bertujuan untuk menginvestigasi hubungan antara perilaku siswa dengan kemampuan berbicara bahasa inggris serta menemukan jenis dari perilaku motivasi yang memberikan pengaruh terbesar terhadap kemampuan berbicara bahasa inggris. Penelitian ini merupakan penelitian kuantitatif. Subyek dalam penelitian ini sebanyak 40 siswa pada tahun ke dua di SMAN 1 Pringsewu. Teknik pengumpulan data yang digunakan adalah kuenioner dan transactional English speaking test. Disain penelitian adalah ex post facto design. Hasil penelitian menunjukan bahwa nilai korelasi antara kedua variable adalah 0.65 dan nilai pengaruhnya adalah 0.421. Lebih jauh, ditemukan data bahwa intensitas berdampak 20.9%, perhatian berdampak 30.5%, dan intensitas berdampak 18.2% terhadap kemampuan berbicara siswa. Berdasarkan pada hasil, dapat disimpulkan bahwa ada hubungan antara perilaku motivasi siswa dan kemampuan berbicara bahasa inggris mereka serta perhatian memberikan dampak terbesar.The objectives of this research are to investigate the relationship between students motivational behavior and their English speaking proficiency and to find the kinds of motivational behavior that gives most influence to the students speaking proficiency. This is quantitative research. The subject consists of forty students of second grade at SMAN 1 Pringsewu. The data collecting technique used were questionnaire and transactional English speaking test. The design that was used was ex post facto design. The result of this research showed that the coefficient correlation was 0.650 and the coefficient influences value of X toward Y was 0.421. Furthermore, it was found that intensity gave 20.9%, attention gave 30.6%, and intensity gave 18.2% contribution to the students speaking proficiency. Based on the result, it can be concluded that there is relationship between students motivational behavior and their English speaking proficiency and attention gives most influence.Keywords: motivational behavior, english speaking proficiency, relationship
