The global independence of the external auditor is decomposed into real and perceived independence. The aim of this article is to analyze the factors enhancing the global independence of the Tunisian auditor by classifying them as factors related to the auditor, the auditing firm and the audited company. In one hand, our results shows that training, sector specialization and the audit committee reinforce real and perceived auditor’s independence. In fact, the auditor with a higher degree of education is enables to issue an unbiased audit report. The sector specialization guarantees the auditor's ability to be rigorous and independent during the audit assignment. The audit committee which has a legitimate and informative power limits any pressure on auditor’s independence. In addition, the audit tenure has a negative effect on the perceived independence and the voluntary rotation decreases the real independence because managerial pressures can force the auditor to give a favorable opinion on the financial statements and the rotation can affects the auditor's perception of his future fees. We can therefore conclude that achieving a global independence of the auditor is a difficult task because of the ambiguity of the assessment of the real independence of the Tunisian auditor.