Critical thinking (CT) is a generic attribute that is greatly valued across academic disciplines in higher education, and around the globe. It is also defined as one of the graduate attributes of higher education for the sample private university where this research was conducted, as it is perceived that CT helps the graduate to become ‘engaged citizens’ in the twenty-first century. Despite the well-documented importance of CT, its assessment remains a challenge. This study addresses this challenge through the systematic development and field-testing of a rubric for assessing critical thinking in a multidisciplinary context in higher education. A multidisciplinary group of faculty (i.e. education, nursing, medicine) from the sample university partnered with a policy research group in Canada to translate this plan into action. The development of the assessment tool followed a multi-step process including: (i) identification of the main elements of CT; (ii) choice of a rubric format; (iii) adaptation of the currently available relevant rubrics; and, (iv) field testing and establishment of the reliability of the rubric. The process resulted in the development of a holistic template, the Assessment of Critical Thinking (ACT) rubric. Two versions of the rubric have been field tested on a sample (n=59) of students drawn from different entities of the sample university. The data collected was subjected to psychometric analysis which yielded satisfactory results.