Contractual provisions related to delay and extension of time are often written in difficult language or presented in a scattered manner in construction contracts. This could lead to confusion and misunderstanding by the different parties as to rights and responsibilities. Thus, it is not surprising that poor contract administration is always listed among the top reasons for conflicts, claims, and disputes in the construction industry. The goal of this paper is to present contract administration guidelines for appropriate utilization of the provisions related to extension of time under the most widely used standard design-build contracts. This is particularly valuable bearing in mind the complexity of addressing construction delays in general, as well as the growing popularity of design-build delivery methods in particular. To address this goal, the authors (1) analyzed the provisions related to extension of time under standard design-build contracts published by a range of professional bodies and institutions; (2) highlighted the differences and commonalities among the studied contracts in a comparative analysis form; and (3) developed a checklist of causes and questions to provide an easy-to-use systematic process to allow for a more robust process for managing claims for extension of time. The presented checklist acts as a tool for assessing and enhancing contract administration for extension of time under design-build contracts. The checklist also provides associated parties with guidelines for drafting contractual clauses related to extension of time under new design-build contracts. This study is expected to promote effective and efficient contract administration of requests for extension of time, thus minimizing conflicts, claims, and disputes as well as enabling associated parties to mitigate the related time and cost negative impacts on their projects.