- MunEDA GmbH
- NanGate, Inc.
- Nannor Technologies Inc.
- Nascentric, Inc.
- Nassda Corporation
- National Research Council of Canada
- National Semiconducor
- Neolinear, Inc.
- NetSpeed Systems
- Network Design Tools, Inc.
- NeuroCAD Inc.
- Nexsyn Design Technology Inc
- Next Device Limited
- NextOp Software, Inc.
- NI (formerly National Instruments)
- Nimbic, Inc.
- NM Electronics
- Northwest Logic, Inc.
- Nova
- Novarm Limited
- Novas Software
- Novelics
- Novo Systems Corp
- Novocell Semiconductor, Inc.
- NP Komplete Technologies BV
- nSys Design Systems Private Limited
- Numerical Technologies, Inc.
- NuPGA
- Nusym Technology, Inc.
- NXP CMOS IP
- NXP Semiconductor
- Oasys Design Systems Inc.
- Obsidian Software
- OCP-IP
- Omnicad Corp.
- OneSpin Solutions GmbH
- Onto Innovation
- OPC Technology
- Open Networks Engineering
- Open SystemC Initiative
- Open Verilog International
- Open Virtual Platforms
- Open-Silicon, Inc.
- OptEM Engineering Inc.
- Optic2Connect Pte Ltd
- Optical Internetworking Forum (OIF)
- Optical Research Associates LLC
- Optimal Corporation
- Optimal Solutions, Inc.
- OptimalPlus
