GEI Consultants, Inc. | 24,423 followers on LinkedIn. GEI Consultants, Inc. is a consulting engineering firm delivering professional services that improve our world’s built environment. With more than 1,500 staff and over 60 offices in North America, GEI is a leader in providing multi-disciplined engineering and environmental services to a range of private and public sector clients, both domestically and abroad. As part of the employee-owned GISI Consulting Group, clients have access to our deep expertise empowered by the resources of a worldwide platform.