The study investigated the effect of forensic Accounting Techniques on financial crimes in Nigeria with a study of Plateau State Internal Revenue Service in Plateau State. A survey design was adopted for the study. In this study the population is the staff of Plateau State Internal Revenue Service. The service has a total population of 376 staff. Taro Yamane formula for sample size determination was used to ascertain the sample size for this study to be 194. The study employed the use of structured questionnaire as method of data collection and the hypotheses were tested using multiple regression as method of data analysis. Findings shows that data mining technique had a positive and significant effect on financial crime in Nigeria; ratio analysis technique had a negative and significant effect on financial crime in Nigeria and analyzing accounting records techniques have positive and significant effect on financial crime in Nigeria. The study recommended Plateau State Internal Revenue Service in Nigeria should select data mining software that integrates with existing accounting systems and Plateau State Internal Revenue Service in Nigeria should maintain the services of forensic accountants to review their financial statements and transactions at the end of the period of transactions.