The most common method for resolving water-in-oil (W/O) emulsion is chemical demulsification. Bottle test is a recommended procedure to analyze a combination of essential parameters such as the demulsifier dosage, residence time, heat, degree of agitation to generate the emulsion and agitation effects after demulsifier injection. It is an extensive and time-consuming selection procedure. Furthermore, the previous demulsifier selection guideline reported in the literature had limitations and was not suitable for the Southeast Asia region. This study describes the development of a new demulsifier selection guideline that relates the demulsifier properties to the crude oil characteristics and is more representative for resolving emulsions in Southeast Asia environment. In developing the selection guideline, four types of synthetic crude were used, with the crude API ranging from 27° to 40°. Sixteen demulsifiers with a relative solubility number (RSN) ranging from 11 to 21 were evaluated comprising resin alkoxylate and modified polyol base demulsifiers. An emulsion test matrix was developed by creating emulsions with different wax contents, asphaltene content and solid contents in the crude oil; then, the demulsifier was screened for all the matrices. Based on the demulsification bottle test completion for all the test matrices, the demulsifier selection guideline was developed and then validated with the blind test in resolving emulsions from the actual crude. The validation results achieved an 86.7 match rate between the guideline output and the lab experimental result. This proved that good agreement had been established between the demulsifier properties and the crude characteristics. © 2023 Hadhirah Halim N., M. Saaid I., Ravindra Panuganti S.