- IPextreme, Inc.
- iRoC Technologies SA
- ISSC Technology Corporation
- Japanese customers of Cadence software
- Jasper Design Automation
- Jazz Semiconductor, Inc.
- JCET
- Jedat Inc.
- JEDEC
- Juniper Networks, Inc.
- K2 Technologies, Inc.
- Kandou Bus
- Keil
- Keysight Technologies
- Kilopass Technology Inc.
- Kimotion Technologies
- KLA
- KLA-Tencor
- Knowlent Corporation
- Kozio, Inc.
- L-3 Communications
- Lam Research
- Lattice Semiconductor
- Leda Design, Inc.
- Leda SA
- Leuven Industrial Software Company
- Library Technologies, Inc.
- Lighthouse Design Automation, Inc.
- Logic Automation, Inc.
- Logic Modeling Corporation
- Logic Modeling Systems Inc.
- Logical Devices, Inc.
- LogicVision, Inc.
- Logipard AB
- Looking Glass Studios
- Lorentz Solution, Inc.
- LSI Logic
- Luminescent Mask Synthesis technology
- Luminescent Technologies
- Magillem
- Magma Design Automation Inc.
- Magwel NV
- Marple Technologies
- Marvell Technology Group Ltd.
- Massachusetts Institute of Technology
- Massteck Ltd.
- Mathtools Ltd
- Mathworks
- Maxim Integrated Inc.
- Memory BIST Division of iRoC
