| 1551 | Liqueurs, manufacturing | |
| 5122 | Liqueurs, wholesale | |
| 2411 | Liquid air, manufacturing | |
| 3313 | Liquid analysis instruments, industrial process type, manufacturing | |
| 3420 | Liquid bulk trailer, manufacturing | |
| 5149 | Liquid chemical fertilizers, wholesale | |
| 6023 | Liquid chemicals, bulk tank truck service | |
| 3312 | Liquid chromatographic instruments, laboratory type, manufacturing | |
| 3313 | Liquid concentration instruments, industrial process type, manufacturing | |
| 3420 | Liquid containers specially designed for use by one or more modes of transportation, manufacturing | |
| 3312 | Liquid flow meters, manufacturing | |
| 3312 | Liquid level controls, residential and commercial heating types, manufacturing | |
| 3313 | Liquid level instruments, industrial process type, manufacturing | |
| 2812 | Liquid oxygen tanks, manufacturing | |
| 6023 | Liquid petroleum products trucking, local | |
| 6023 | Liquid petroleum products trucking, long-distance | |
| 1542 | Liquid sugar, made from purchased raw cane sugar | |
| 1542 | Liquid sugar, made from sugar beets | |
| 1542 | Liquid sugar, made in sugarcane mills | |
| 5149 | Liquid waste recovery (collection only) | |
| 1110 | Liquified petroleum gases (LPG) natural | |
| 2320 | Liquified petroleum gases (LPG), made in petroleum refineries | |
| 1110 | Liquified petroleum gases from natural gas, production, mining | |
| 5141 | Liquified petroleum gases, wholesale | |
| 6412 | Liquor delivery services (dial-a-bottle) | |
| 5220 | Liquor stores | |
| 1543 | Liquor, chocolate, made from cacao beans | |
| 5122 | Liquor, distilled, wholesale | |
| 5122 | Liquor, wholesale | |
| 1551 | Liquor-based coolers, manufacturing | |
| 1543 | Liquorice candy, manufacturing | |
| 5122 | Liquorice confectionery, wholesale | |
| 1551 | Liquors, distilling and blending (except brandy) | |
| 3000 | List finders and rotary address files, manufacturing | |
| 7020 | Listing service, real estate | |
| 7499 | Literary agents | |
| 2411 | Litharge, manufacturing | |
| 2411 | Lithium compounds, not specified elsewhere by process, manufacturing | |
| 1421 | Lithium mineral mining | |
| 2422 | Lithographic inks, manufacturing | |