ABSTRAK Penelitian ini bertujuan untuk menguji pengaruh Rasio Efisiensi, Risk Aversion, Risiko Kredit dan Transaction Size terhadap Net Interest Margin pada perbankan yang terdaftar di Bursa Efek Indonesia. Variabel independen dalam penelitian ini adalah Rasio Efisiensi yang di proksikan dengan beban operasional terhadap pendapatan operasional (BOPO), Risk Aversion diproksikan dengan Capital Adequate Ratio (CAR), Risiko Kredit diproksikan dengan Non Performing Loan (NPL) dan Transaction Size diukur dengan Log Total Kredit. Sedangkan variabel dependen dalam penelitian ini adalah Net Interest Margin. Sampel dalam penelitian ini menggunakan data panel 27 perusahaan perbankan di Indonesia selama periode 2013-2016 dan dianalisis menggunakan metode estimasi Fixed Effect Model menggunakan program Eviews 10.0. Hasil penelitian menunjukkan bahwa : (1) Rasio Efisiensi berpengaruh negatif dan signifikan terhadap Net Interest Margin, (2) Risk Aversion berpengaruh positif dan signifikan terhadap Net Interest Margin, (3) Risiko Kredit berpengaruh positif namun tidak signifikan terhadap Net Interest Margin, (4) serta Transaction Size berpengaruh negatif dan signifikan terhadap Net Interest Margin. Kata Kunci : Rasio Efiesiensi, Risk Aversion, Risiko Kredit, Transaction Size dan Net Interest Margin ABSTRACT This study aims to examine the effect of Efficiency Ratios, Risk Aversion, Credit Risk and Transaction Size to Net Interest Margin in banking companies that listed in Indonesia Stock Exchange (IDX). The independent variables in this research are Ratio Efficiency that proxied by operational expense to operating income (BOPO), Risk Aversion is proxy with Capital Adequate Ratio (CAR), Credit Risk proxied with Non Performing Loan (NPL) and Transaction Size that proxied by Log Total Loan . While the dependent variable in this research is Net Interest Margin. This study use panel data of 27 banking companies in Indonesia during the period 2013 until 2016 and analyzed with Fixed Effect Model estimation method using Eviews 10.0 program. The results showed that: (1) Ratio Efficiency has negative and significant effect to Net Interest Margin, (2) Risk Aversion has positive and significant effect to Net Interest Margin, (3) Credit Risk has positive but not significant effect to Net Interest Margin, (4) and Transaction Size have negative and significant effect to Net Interest Margin. Keywords : Efficiency Ratio, Risk Aversion, Credit Risk, Transaction Size and Net Interest Margin