研究指出IT專案的失敗主要可歸咎於欠缺高階主管支持。然而，高階主管支持與否卻不在專案團隊的控制範圍之內。本論文從三個理論觀點（認知失調、說服和社會資本理論）分別探討IT 專案團隊如何取得高階主管對專案的支持。三個實徵研究分別採用個案研究和問卷調查法。研究發現指出：(1) 在專案初期，當主管對專案態度為負面時，持續請求主管幫忙會正面影響主管對IT專案的看法，因為這會帶來主管在行為和認知上的失調，進而促使他們接受專案；(2) 在多數IT專案情況下，專案團隊可以透過「理性說服」和「交換互惠」，去影響高階主管的認知和情緒，進而影響主管對專案的支持；(3) IT專案團隊可以透過建立新的、或挪用已存在的社會資本（與高階主管之間，和與那些可以左右主管態度的人），來影響高階主管對IT專案的持續支持。;Research has argued a major reason for IT project failure is the lack of top management support. However, obtaining top management support is often considered outside the project team’s control. This thesis investigates how an IT project team can obtain such support from three perspectives—cognitive dissonance, persuasion, and social capital. Three empirical studies (two case studies and one survey study) are conducted by using qualitative and quantitative data respectively. It is found that (1) under the condition of low top management support, a series of favors performed by top management influences provision of their support because doing favors induce dissonance and attitudinal change in top management; (2) under most conditions, an IT project team can directly influence not only cognition, but also emotion of top management to support an IT project through different influence tactics (i.e., rational persuasion and exchange); and (3) an IT project team can obtain continuous top management support by building social capital, and mobilizing existing social capital—directly with top management, or indirectly with individuals with influence on top management.