The North American Industry Classification System (NAICS) code for IT (Information Technology) consulting services is 541512. This code is designated for businesses primarily engaged in providing expertise in the field of information technologies through one or more of the following services: writing, modifying, testing, and supporting software to meet the needs of a particular customer; planning and designing computer systems that integrate computer hardware, software, and communication technologies; and/or providing on-site management and operation of clients' computer systems and/or data processing facilities. It's a part of the broader category of Computer Systems Design and Related Services, which falls under the sector 5415.
Remember, when selecting a NAICS code for your business, it's important to choose the one that most closely matches your primary business activity. If your services span multiple categories, you might need to determine which part of your business represents the largest portion of your operations or income.