| Discover Energy Systems | Richmond, British Columbia | Visit site |
| Divea | Sion, Valais | Visit site |
| Diversified Construction of Oklahoma | Edmond, Oklahoma | Visit site |
| Diverxia | Paterna, Valencia | Visit site |
| Dividend | San Francisco, California | Visit site |
| Diwakar Solar | Jaipur, Rajasthan | Visit site |
| Doart Energy | Islamabad, Islamabad Capital Territory | Visit site |
| Dogma Energia | Casciana Terme Lari, Pisa | Visit site |
| Doha Petroleum Construction Co. W.L.L | Doha | Visit site |
| Doman Energy Group | Raleigh, North Carolina | Visit site |
| Dominion Energy Solutions | Richmond, Virginia | Visit site |
| Domolynx | Saint-Laurent, Quebec | Visit site |
| Doncaster Cables | Doncaster, England | Visit site |
| Dongguan Pengjin Machinery Technology Co.,Ltd. | Dongwan Shi, Guangdong | Visit site |
| Dongguan Yuanze ELectric Co.,Ltd | Dongwan Shi, Guangdong | Visit site |
| Dongjin Group Bangladesh | Shenzhen Shi, Guangdong | Visit site |
| Doosan Enerbility | Changwon-si, Gyeongsangnam-do | Visit site |
| Doosan Fuel Cell | Seoul | Visit site |
| Doosan GridTech | Bellevue, Washington | Visit site |
| Doosan Lentjes | Ratingen, North Rhine-Westphalia | Visit site |
| Dornier Group | Berlin | Visit site |
| Dornier Hinneburg GmbH | Willstätt, Baden-Württemberg | Visit site |
| Dotz Nano Ltd. | Kfar Sava, Central District | Visit site |
| Doyle Land Services, Inc. | New Orleans, Louisiana | Visit site |
| Dr. Spang Ingenieurgesellschaft | Witten, North Rhine-Westphalia | Visit site |
| Dragados Canada, Inc. | Toronto, Ontario | Visit site |
| DragonWear® | Tukwila, Washington | Visit site |
| Dravske elektrarne Maribor | Maribor | Visit site |
| Dredge Masters Ghana Limited | Accra, Greater Accra | Visit site |
| Drishti Foundation Trust | Ahmedabad, Gujarat | Visit site |
| Drive System Design | Leamington Spa, England | Visit site |
| Drone Drafting | Brooklyn, NY | Visit site |
| DuPont | Wilmington, Delaware | Visit site |
| Ducab | Dubai | Visit site |
| Dudley Land Company | Oklahoma City, Oklahoma | Visit site |
| Duncan | Minneapolis, Minnesota | Visit site |
| Dunia | Berlin | Visit site |
| Dura-Line | Knoxville, Tennessee | Visit site |
| DuraBante LLC | Sparks Glencoe, Maryland | Visit site |
| DuraLabel | Beaverton, OR | Visit site |
| Duraco Ltée | Van Wert, Ohio | Visit site |
| Durasol Energi | Gurugram, Haryana | Visit site |
| Durasolar BV | Didam, Gelderland | Visit site |
| Duratron | Dubai | Visit site |
| Dutch Solar Energy | Tilburg, North Brabant | Visit site |
| Dutchland | Gap, Pennsylvania | Visit site |
| Duurzaam Opgewekt | Geldermalsen, Gelderland | Visit site |
| Dyn365Pros | Carlsbad, California | Visit site |
| Dynami Battery Corp | Binghamton, New York | Visit site |
| Dynamic Controls Inc. | East Peoria, Illinois | Visit site |
| Dynamic Systems, Inc. | Austin, Texas | Visit site |
| Dynamysk Automation Ltd. | Calgary, Alberta | Visit site |
| Dynergy Energy Management | Vaughan, Ontario | Visit site |
| Dyness | Suzhou Shi, Jiangsu | Visit site |
| DynoRaxx | Buffalo, New York | Visit site |
| DynoRotor Inc. doing business as AquaGen | Hollywood, Florida | Visit site |
| d & d brandschutzsysteme gmbh | Oberhausen, North Rhine-Westphalia | Visit site |
| dGEN Energy Partners, Inc | Buffalo, Wyoming | Visit site |
| dbHMS | Chicago, Illinois | Visit site |
| de MATRIX | Groningen | Visit site |