This report presents a comprehensive study on airfoil self-noise, focusing on the development and validation of a prediction method for various self-noise mechanisms. The study is based on a series of aerodynamic and acoustic tests conducted in an anechoic wind tunnel on two- and three-dimensional airfoil blade sections. The tests involved different NACA 0012 airfoil models with chord lengths ranging from 2.5 to 61 cm, tested at wind tunnel speeds up to Mach 0.21 and angles of attack from 0° to 25.2°. The report identifies and models five self-noise mechanisms: turbulent boundary-layer-trailing-edge (TBL-TE) noise, separated-boundary-layer and stalled-airfoil flow noise, vortex shedding due to laminar-boundary-layer instabilities, vortex shedding from blunt trailing edges, and tip vortex formation noise. The data used for normalization and scaling are derived from hot-wire probe measurements of boundary-layer thicknesses and integral parameters at the trailing edge. The acoustic measurements are processed to extract clean self-noise spectra by identifying and editing out extraneous test rig noise. The resulting spectra are presented in 1/3-octave format and used to develop scaling laws for each self-noise mechanism. These scaling laws are then compared with published data from three studies on different airfoil shapes, which were tested at higher Mach and Reynolds numbers. The report also includes an application of the prediction method to a large-scale helicopter rotor broadband noise test, demonstrating its effectiveness in predicting self-noise characteristics. A computer code for the prediction method is provided, along with detailed descriptions of data processing techniques, noise directivity functions, and the application to a helicopter rotor study.This report presents a comprehensive study on airfoil self-noise, focusing on the development and validation of a prediction method for various self-noise mechanisms. The study is based on a series of aerodynamic and acoustic tests conducted in an anechoic wind tunnel on two- and three-dimensional airfoil blade sections. The tests involved different NACA 0012 airfoil models with chord lengths ranging from 2.5 to 61 cm, tested at wind tunnel speeds up to Mach 0.21 and angles of attack from 0° to 25.2°. The report identifies and models five self-noise mechanisms: turbulent boundary-layer-trailing-edge (TBL-TE) noise, separated-boundary-layer and stalled-airfoil flow noise, vortex shedding due to laminar-boundary-layer instabilities, vortex shedding from blunt trailing edges, and tip vortex formation noise. The data used for normalization and scaling are derived from hot-wire probe measurements of boundary-layer thicknesses and integral parameters at the trailing edge. The acoustic measurements are processed to extract clean self-noise spectra by identifying and editing out extraneous test rig noise. The resulting spectra are presented in 1/3-octave format and used to develop scaling laws for each self-noise mechanism. These scaling laws are then compared with published data from three studies on different airfoil shapes, which were tested at higher Mach and Reynolds numbers. The report also includes an application of the prediction method to a large-scale helicopter rotor broadband noise test, demonstrating its effectiveness in predicting self-noise characteristics. A computer code for the prediction method is provided, along with detailed descriptions of data processing techniques, noise directivity functions, and the application to a helicopter rotor study.