D
- Design Gateway
- DMC Tools
- D3 Semiconductor
- DAVE Embedded Systems
- Davies Molding
- DB Unlimited
- DBM Optix
- Dell
- Delta Electronics
- Deltron
- Desco Tools
- Desco
- Doodle Labs
- DFRobot
- Dialight
- Dialog Semiconductor
- Digi International
- Digilent
- Digital View
- Diode Laser Concepts
- Diodes Incorporated
- DIOO Microcircuits
- Diptronics
- DLP Design