Penelitian ini bertujuan untuk mengetahui (1) bagaimana efektivitas pajak daerah di Kabupaten Nunukan terhadap Pendapatan Asli Daerah , (2) bagaimana efisiensi pajak daerah terhadap Pendapatan Asli Daerah Kabupaten Nunukan, (3) bagaimana kontribusi pajak daerah terhadap Pendapatan Asli Daerah Kabupaten Nunukan. Penelitian ini menggunakan metode deskriptif kuantitatif. Teknik pengumpulan data adalah dokumentasi dan studi pustaka. Data yang digunakan adalah target pajak daerah, realisasi pajak daerah dan Pendapatan Asli Daerah. Analisis data menggunakan analisis efektivitas, analisis efisiensi dan analisis kontribusi. Hasil penelitian ini adalah: (1) kriteria tingkat efektivitas pajak daerah terhadap Pendapatan Asli Daerah kabupaten nunukan tahun 2017 - 2021 sangat efektif, (2) kriteria tingkat efisiensi pajak daerah terhadap Pendapatan Asli Daerah Kabupaten Nunukan tahun 2017 - 2021 sangat efisien, (3) kriteria tingkat kontribusi pajak daerah terhadap Pendapatan Asli Daerah Kabupaten Nunukan tahun 2017 - 2021 adalah sedang, (4) kriteria tingkat kontribusi pendapatan hasil daerah terhadap anggaran pendapatan dan belanja daerah (APBD) Kabupaten Nunukan tahun 2017 - 2021 adalah sangat kurang.

Kata Kunci : Efektivitas, Efisiensi, Kontribusi, Pajak Daerah, Pendapatan Asli Daerah (PAD), Anggaran Pendapatan dan Belanja Daerah (APBD).

The present research aimed to find out (1) the effectiveness of district tax in Nunukan Regency towards district own source revenue, (2) the efficiency of district tax towards district own source revenue in Nunukan Regency, and (3) the contribution of district tax to district own source revenue of Nunukan Regency. This research employed a quantitative descriptive method. Data collection techniques were documentation and literature study. The data were in the forms of district tax target, district tax realization, and district own source revenue. Data were analyzed using effectiveness analysis, efficiency analysis, and contribution analysis. The results of this research were: (1) the criteria for the level of effectiveness of district tax towards district own source revenue of Nunukan Regency in 2017-2021 was very effective, (2) the criteria for the level of efficiency of district tax towards district own source revenue of Nunukan Regency in 2017 - 2021 was very efficient, (3) the criteria for the contribution level of district tax towards district own source revenue of Nunukan Regency in 2017 - 2021 was moderate, (4) the criteria for the level of contribution of district income towards district revenue and expenditure budget of Nunukan Regency in 2017-2021 was very low. Keywords: Effectiveness, Efficiency, Contribution, District Tax, District Own Source Revenue, District Revenue and Expenditure Budget.