This peer review conceptual paper explores the impact of internal audit on improving anti-money laundering (AML) and counter-terrorist financing (CTF) controls in Nigeria. The study aims to examine the role of internal audit in enhancing AML/CFT controls and to identify any limitations or criticisms of internal audit in this context. The researchers conducted a search for research papers published between 2015 and 2023 on the impact of internal audit in improving and AML/CTFT suing the Google Scholar Search Engine, EBSCO Hosts, Science Direct, JStor and Emeralds. The Selection Criteria for the relevant articles are the keywords in the theme of the research. The selected journals were reviewed, analysed and synthesized. The paper concludes that internal audit plays a crucial role in improving AML/CFT controls in Nigeria and suggests that internal auditors should be more involved in the design and implementation of AML/CFT controls. The paper recommends that the internal auditor must be equipped with the in-depth knowledge of the various schemes through which criminals launder money and the evolution of the various money laundering and terrorism financing schemes and how ICT tools can be used to deter these white collar crimes. The study further recommends a stronger need for collaboration between the internal auditors and the Nigerian Financial Intelligence Unit (NFIU) and the AML/CTF Department of the Central Bank of Nigeria (CBN) for information sharing on new standards and best practices to combat money laundering and counter terrorism financing