This research explores postgraduate students' attitudes and use of Artificial Intelligence (AI) tools in academic writing, using the Theory of Planned Behavior (TPB). Guided by the mixed method approach, quantitative and qualitative measures like questionnaires and interviews were adopted to gather data from postgraduate students. Descriptive statistical tools like frequencies, means and SD were used to analyze responses from 339 postgraduate students, focusing on the perceived usefulness and actual usage of AI tools in their writing endeavors. The findings, presented through means and standard deviations, indicate an overall positive attitude towards AI tools. The students perceive AI as beneficial for improving grammar, preventing plagiarism, generating ideas, and enhancing overall writing proficiency. However, a lack of consensus is evident, with varied responses and inflated standard deviations suggesting differing opinions among respondents. Subjective norms play a crucial role in influencing students' decisions to use AI tools. Friends, colleagues, and lecturers significantly influence their perception and adoption of AI tools in academic writing. Although cautioned about excessive reliance, the influence of positive testimonials contributes to the widespread adoption of AI tools among postgraduate students. In terms of actual usage, the study reveals that postgraduate students frequently employ AI tools, primarily for idea development, spelling checks, paraphrasing, coherence, and searching for relevant literature. While some students appreciate the convenience and time-saving aspects of AI, others express concerns about potential detrimental effects on critical thinking and creativity. In conclusion, the research underscores the varied attitudes and usage patterns of postgraduate students regarding AI tools in academic writing. While many acknowledge the benefits, caution is advised to prevent overdependence and preserve critical thinking skills. The findings contribute valuable insights for educators and institutions seeking to integrate AI tools effectively into postgraduate education.