An accounting information system assists managers in making critical decisions by enhancing the firm's operational performance and long-term investment methods. Business uses accounting information system to collect, store, manage, process, retrieve and report data so it can be used by accountants, consultants, business analysts, managers, chief financial officers, auditors, regulators and tax agencies, among others. Hence, the study sought to examine the influence of accounting information systems on decision-making in audit firms in the USA. The study adopted the descriptive research design. The study included employees from Grant Thornton LLP. The collection of data was collected through stratified random sampling. The study used questionnaires to collect the data. The study used descriptive and inferential statistics to collect the data. The inferential statistics helped the study to examine the relationship between variables. The study findings showed that the accounting information system is positively and significantly related to decision-making (β=.901, p=0.009). It is concluded that a sound accounting information system needs to be simple and attain cost benefits balance, timeliness, accuracy, quality and conciseness. An information system is a formal process for collecting data, processing the data into information and distributing that information to users. The purpose of an accounting information system is to collect, store, and process financial and accounting data and produce informational reports that managers or other interested parties can use to make business decisions. The study recommended that audit firms consider and put proper measures to ensure that the accounting information system effectively influences decision-making. The firm should employ more well-informed workers about bookkeeping and establish a systematic strategy of executing the accounting systems to eliminate any difficulty. It is also recommended that accountants, consultants, business analysts, managers, chief financial officers, auditors, regulators and tax agencies rely on accounting information systems when making decisions.