Abstrak: Implementasi Just in Time Layanan Penerbitan Nomor Pokok Wajib Pajak. Penelitian ini memiliki tujuan untuk menganalisis penerapan Just-in-Time (JIT) untuk proses penerbitan Nomor Pokok Wajib Pajak (NPWP) melalui Pelayanan Terpadu Satu Pintu pada Badan Koordinasi Penanaman Modal (BKPM). Metode yang digunakan adalah deskripsi kualitatif dengan pendekatan studi kasus. Hasil penelitian menunjukkan bahwa layanan penerbitan NPWP merupakan implementasi konsep JIT dengan kesesuaian karakteristik yakni pull system, cellular manufacturing, serta time and resources reduction. Selain itu, keseluruhan proses layanan jasa dapat dilakukan oleh satu petugas multiskilled dalam satu loket. Abstract: Just in Time Implementation on The Issuance Of Taxpayer Identification Number. This study aims to analyze the implementation of Just-in-Time (JIT) for the issuance of a Taxpayer Identification Number (NPWP) through one stop integrated services at Investment Coordinating Board. The method of this research is a qualitative description with case study approach. The results showed that NPWP issuance services represent as an implementation of JIT concept with its characteristics of pull systems, cellular manufacturing, and time and resources reduction. In addition, the entire service process can be performed by one multiskilled officer in a counter.