Penelitian ini bertujuan untuk mengetahui dan menganalisis pengaruh komunikasi internal, motivasi kerja, dan kepemimpinan kepala sekolah terhadap kinerja guru administrasi perkantoran di SMK Swasta se-Kota Semarang baik secara partial maupun simultan. Populasi dalam penelitian ini adalah seluruh guru mata pelajaran produktif administrasi perkantoran di SMK Swasta se-Kota Semarang yang berjumlah 40 guru. Sampel yang digunakan adalah keseluruhan dari populasi (sampel jenuh). Metode pengumpulan data menggunakan kuesioner. Teknik analisis data menggunakan analisis regresi linier berganda, uji asumsi klasik, dan analisis deskriptif persentase. Hasil penelitian menunjukkan bahwa 1) Ada pengaruh positif dan signifikan komunikasi internal, motivasi kerja, dan kepemimpinan kepala sekolah secara simultan terhadap kinerja guru administrasi perkantoran sebesar 69.5%. 2) Ada pengaruh positif dan signifikan komunikasi internal secara parsial terhadap kinerja guru administrasi perkantoran sebesar 31.92%. 3) Ada pengaruh positif dan signifikan motivasi kerja secara parsial terhadap kinerja guru administrasi perkantoran sebesar 12.67%. 4) Ada pengaruh positif dan signifikan kepemimpinan kepala sekolah secara parsial terhadap kinerja guru administrasi perkantoran sebesar 17.47%. Kesimpulan dari penelitian ini adalah ada pengaruh positif dan signifikan antara komunikasi internal, motivasi kerja, dan kepemimpinan kepala sekolah terhadap kinerja guru administrasi perkantoran di SMK Swasta se-Kota Semarang baik secara partial maupun secara simultan. This research aimed to find out and anlayze the influences of internal communication, work motivation, and principal’s leadership toward the performance of office administration teachers in all Private Vocational High Schools in the City of Semarang either simultaneously or partial. The population in this study was all the teachers of productive office administration subject in private vocational high school in the city of Semarang, which were 40 teachers in the total number. The sample was the whole population The method of data collection was questionnaire. The data analysis technique were multiple linear regression, classic assumption test and percentage descriptive analysis. The result of the research showed that: 1) There were positive and significant influence of internal comminication, work motivation, and the principal’s leadership simultaneous toward the performance of office administration teachers which amounted to 69.5%. 2) There were positive and significant influence of internal comminication partial toward the performance of office administration teachers which amounted to 31.92%. 3 ) There were positive and significant influence of work motivation partial toward the performance of office administration teachers which amounted to 12.67%. 4) There were positive and significant influence of principal’s leadership partial toward the performance of office administration teachers which amounted to 17.47%. The conclusion of the research was there were positive and significant influences between internal comminication, work motivation, and the principal’s leadership toward the performance of office administration teachers in all Private Vocational High Schools in the City of Semarang simultaneous and partial.