This paper reviews the issues of concern in writing scale development in English as Second Language (ESL) settings with an intention to provide a useful guide for researchers or writing teachers who wish to develop or adapt valid, reliable and efficient writing scales considering their present assessment situations. With a brief discussion on the rationale behind writing scales, the author considers the process of scale development by breaking it into three phases of design, operationalization and administration. The issues discussed in the first phase include analyzing the samples, deciding on the type of scale and ensuring the validity of its design. Phase two encompasses setting the scale criteria, operationalization of definitions, setting a numerical value, assigning an appropriate weight for each trait, accounting for validity and reliability. The final phase comprises recommendations on how a writing scale should be used.