State licensing boards · verified July 2026
Do diesel mechanics need a license?
The short answer
In most of the United States, no. As of July 2026, 48 states require no license at all to work as a diesel mechanic, 0 leave licensing to cities and counties, and 2 regulate the trade at state level. Where no license exists, the credential employers actually look for is ASE Medium/Heavy Truck (T-series) certification.
48states with no license
0city or county licensing
2state-level licensing
50/50states checked
Which states license diesel mechanics?
2 states regulate this trade at state level. Some license the individual worker; others regulate only the contracting business, which means an employee works under someone else's credential rather than holding one personally. The distinction matters if you plan to work for yourself.
| State | What is regulated | Authority |
|---|---|---|
| Hawaii | The individual worker | Motor Vehicle Repair Industry Board, Hawaii Department of Commerce and Consumer Affairs, Professional & Vocational Licensing Division |
| Michigan | The individual worker | Michigan Department of State (Secretary of State), Business Licensing Section |
Which states require nothing?
48 states impose no licensing requirement on diesel mechanics at all. Their occupational licensing directories list the trades they regulate, and this one is not among them. That is a positive finding rather than missing research: each of these states was checked against its own published list.
| State | What the state publishes |
|---|---|
| Alabama | Alabama does not license diesel mechanics or any automotive repair technicians as an occupation; no state board regulates the trade. The only state requirement attaches to the business, not the worker: repair shops must buy an annual business privilege (tax) license under Ala. Code Title 40 |
| Alaska | Alaska does not license diesel mechanics. The Division of Corporations, Business and Professional Licensing (DCCED) publishes the complete list of professions licensed in Alaska, and no automotive, diesel, truck |
| Arizona | Arizona does not license diesel mechanics or automotive technicians. The Arizona Commerce Authority's official business-licensing guidance explicitly lists auto mechanics as a profession covered by voluntary industry certification rather than state regulatory licensing |
| Arkansas | Arkansas does not license diesel mechanics. The state's official 2025 Directory of Licensed, Certified, and Registered Occupations (Division of Workforce Services) catalogs every occupation licensed by Arkansas boards and agencies, and it contains no license for diesel, bus/truck |
| California | California does not license individual diesel or automotive mechanics - the Bureau of Automotive Repair's licensing page states outright that a BAR license is not required to work as a general automotive repair mechanic. State requirements attach to the repair BUSINESS: any shop that diagnoses |
| Colorado | Colorado does not license diesel mechanics or any automotive repair technicians. The DORA Division of Professions and Occupations' roster of regulated professions contains no mechanic or motor vehicle repair category. The only adjacent state credential is the Diesel Emissions Inspector license |
| Connecticut | Connecticut does not license individual diesel mechanics or technicians. State law instead requires the repair BUSINESS to hold a Motor Vehicle Repairer license from the Connecticut DMV (General Repairer 'R' or Limited Repairer 'L') |
| Delaware | Delaware does not license diesel mechanics or automotive repair technicians. The Division of Professional Regulation's complete list of 37 licensing boards and commissions includes trades such as electricians, plumbers/HVACR, and elevator mechanics |
| Florida | Florida does not license individual diesel mechanics or technicians. Under the Florida Motor Vehicle Repair Act (F.S. 559.901-559.9221), the repair SHOP must register with the Florida Department of Agriculture and Consumer Services |
| Georgia | Georgia does not license diesel mechanics or automotive repair technicians. The Georgia Secretary of State's Professional Licensing Boards Division board list |
| Idaho | Idaho does not license diesel mechanics or any automotive repair occupation. The Division of Occupational and Professional Licenses (DOPL), which administers all of Idaho's state occupational licensing boards, publishes a complete licensed-profession list (contractors, electricians, plumbers, HVAC) |
| Illinois | Illinois does not license diesel mechanics or automotive technicians. The Illinois Department of Financial and Professional Regulation (IDFPR), which regulates more than 100 professions statewide, includes no mechanic, automotive-repair |
| Indiana | Indiana does not license diesel mechanics or automotive technicians. The Indiana Professional Licensing Agency (PLA), which administers all of the state's occupational licensing boards (about 40 professions and 200 license types), lists no mechanic, automotive |
| Iowa | Iowa does not license diesel mechanics or automotive technicians. Iowa Code section 272C.1, which enumerates every professional and occupational licensing board in the state, includes no board for mechanics or vehicle repair, and the Department of Inspections, Appeals, and Licensing |
| Kansas | Kansas does not license diesel mechanics or any automotive repair technicians at the state level. The state's official Business One Stop states that Kansas generally requires no specific licenses or permits for an auto repair business |
| Kentucky | Kentucky does not license diesel mechanics or automotive repair technicians. The Department of Professional Licensing's 25 regulatory boards include no board for mechanics or vehicle repair, and the trades licensed by other agencies (electricians, HVAC, plumbing) |
| Louisiana | Louisiana does not license diesel mechanics or automotive repair technicians at the state level. The US Department of Labor's official License Finder returns no occupational license for 'diesel' in Louisiana, and its 'mechanic' matches for the state are unrelated occupations |
| Maine | Maine does not license diesel mechanics or automotive repair technicians. The Office of Professional and Occupational Regulation's list of 80+ licensed professions includes no automotive repair occupation. The only related individual credential is the Motor Vehicle Inspection Mechanic certificate |
| Maryland | Maryland does not license diesel mechanics or automotive repair technicians. The Maryland Department of Labor's Division of Occupational and Professional Licensing regulates 25 professions (electricians, HVACR, plumbers, stationary engineers) |
| Massachusetts | Massachusetts does not license diesel or truck mechanics. The Division of Occupational Licensure's boards of registration cover trades such as electricians, plumbers and sheet metal workers, but there is no board or license for automotive or diesel repair technicians |
| Minnesota | Minnesota does not license diesel or truck mechanics. The state's official License Minnesota A-Z directory of all state-issued licenses contains no license for mechanics |
| Mississippi | Mississippi does not license diesel or truck mechanics. Searches of the Secretary of State's official register of state agencies, boards and commissions return no licensing body for mechanics or automotive repair; the only motor-vehicle entity, the Mississippi Motor Vehicle Commission |
| Missouri | Missouri does not license diesel or truck mechanics. The Division of Professional Registration's official listing of all professions licensed by its boards contains no mechanic, automotive or diesel repair occupation |
| Montana | Montana does not license or certify diesel mechanics (bus and truck mechanics and diesel engine specialists) at the state level. The Montana Department of Labor & Industry's Business Standards Division portal lists every professional and occupational licensing board/program in the state |
| Nebraska | Nebraska does not license diesel mechanics or automotive technicians at the state level. The Nebraska DMV's licenses-and-permits catalog contains only driver credentials (operator licenses, CDLs, permits) and no mechanic, technician, or repair-shop credential |
| Nevada | Nevada does not license individual diesel mechanics or automotive technicians. The state instead regulates the business: any establishment operating a 'garage' that repairs motor vehicles for the public must register with the Nevada DMV Occupational and Business Licensing division (NRS 487.560) |
| New Hampshire | New Hampshire does not license diesel mechanics or automotive repair technicians. The Office of Professional Licensure and Certification (OPLC) supports 54+ licensing boards and its complete board list contains no automotive or vehicle-repair occupation |
| New Jersey | New Jersey does not license diesel mechanics or general automotive repair technicians as individuals. The Division of Consumer Affairs' complete list of 51 professional boards contains no automotive-repair occupation. The state's vehicle-repair regulation is business-level and niche-specific |
| New Mexico | New Mexico does not license diesel mechanics or auto mechanics at the state level. The state's official professional-licensing directory (Regulation and Licensing Department plus four Environment Department programs) contains no mechanic or vehicle-repair occupation |
| New York | New York does not license individual diesel mechanics or automotive technicians. Regulation operates at the business level: any shop that diagnoses or repairs motor vehicles for compensation |
| North Carolina | North Carolina does not license diesel mechanics or general automotive technicians; the state's official roster of occupational licensing boards (NCAC Title 21) contains no mechanic or vehicle-repair board. The only state credential in this space is the NCDMV safety/emissions inspection mechanic |
| North Dakota | North Dakota does not license diesel mechanics or automotive technicians. North Dakota Century Code Title 43 (Occupations and Professions), the state's complete list of licensed occupations, contains no chapter for mechanics or vehicle repair |
| Ohio | Ohio does not license diesel mechanics or automotive technicians. The state's official license directory routes 'Automobile Repairers' only to the Ohio Board of Motor Vehicle Repair, which registers businesses - collision repair, auto glass, airbag, window tint |
| Oklahoma | Oklahoma does not license diesel or bus/truck mechanics at the state level. The state's official Occupational Licensing Directory (386 licensed occupations) contains no automotive, diesel, or truck mechanic license |
| Oregon | Oregon does not license diesel or bus/truck mechanics. The state's official Business Xpress License Directory contains no automotive repair or vehicle mechanic license |
| Pennsylvania | Pennsylvania does not license diesel or bus/truck mechanics. None of the 29 licensing boards under the Department of State's Bureau of Professional and Occupational Affairs covers vehicle repair technicians (the only vehicle board regulates manufacturers, dealers) |
| Rhode Island | Rhode Island does not license diesel or bus/truck mechanics. DLT Professional Regulation licenses 67 trade jobs (electricians, hoisting engineers, pipefitters, refrigeration technicians, fire sprinkler fitters, sheet metal workers, plumbers) |
| South Carolina | South Carolina does not license diesel or bus/truck mechanics. SC Code Title 40 (Professions and Occupations), which establishes the state's occupational licensing boards under LLR, contains no chapter for automotive or diesel mechanics |
| South Dakota | South Dakota does not license diesel mechanics, bus/truck mechanics, or any vehicle repair technicians at the state level. The Department of Labor and Regulation's roster of licensing boards and commissions covers trades such as electricians and plumbers but includes no automotive or diesel repair |
| Tennessee | Tennessee does not license diesel mechanics or any motor-vehicle repair technicians. The Department of Commerce and Insurance's Division of Regulatory Boards (21 programs) includes no mechanic or vehicle-repair license, and the Tennessee Motor Vehicle Commission regulates only manufacturers |
| Texas | Texas does not license diesel mechanics or vehicle repair technicians. The Texas Department of Licensing and Regulation (TDLR), the state's umbrella occupational licensing agency, has no mechanic or vehicle-repair program (its automotive-adjacent programs are limited to tow companies) |
| Utah | Utah does not license diesel mechanics or any vehicle repair technicians. The Division of Professional Licensing (DOPL), Utah's occupational licensing agency, publishes a complete list of licensed professions that contains no automotive, diesel, or vehicle-repair occupation |
| Vermont | Vermont does not license diesel mechanics or vehicle repair technicians. The Office of Professional Regulation's comprehensive list of regulated professions contains no automotive or diesel repair occupation, and none of the professions regulated outside OPR |
| Virginia | Virginia does not license diesel or automotive mechanics. The Department of Professional and Occupational Regulation (DPOR), which oversees all of Virginia's regulated occupations across 19 boards |
| Washington | Washington does not license diesel or automotive mechanics. The state's official professional-license directory (WA.gov / Department of Licensing) contains no credential for vehicle repair technicians; the only vehicle-related licenses are business licenses such as vehicle dealer |
| West Virginia | West Virginia does not license diesel or automotive mechanics. The WV Division of Labor, the state's occupational licensing agency for the trades, licenses only construction-related occupations (contractors, HVAC technicians, plumbers, elevator mechanics) |
| Wisconsin | Wisconsin does not license diesel or automotive mechanics. The Department of Safety and Professional Services (DSPS), which regulates more than 200 credential types including the construction trades |
| Wyoming | Wyoming does not license diesel or automotive mechanics. The state's official 2025 Directory of Licensed Occupations, published by the Department of Workforce Services, covers roughly 100 state-licensed occupations and includes no automotive, diesel |
Source: state occupational licensing directories and boards. Verified July 2026.
What do you need instead of a license?
No license does not mean no credential. The qualification employers and inspectors actually ask for is ASE Medium/Heavy Truck (T-series) certification. It is issued by an industry body rather than a state, which is why it works across state lines where a license would not, and why it is worth holding even in the 2 states that do regulate the trade.
Why does this vary so much between states?
Occupational licensing is a state power, and states have made genuinely different judgments about which trades carry enough public-safety risk to justify a license. Work that can burn a building down or contaminate a water supply tends to be licensed everywhere. Work whose failures are commercial rather than dangerous is usually left to employers and industry certification. Where a state regulates the contracting business but not the worker, the reasoning is usually consumer protection rather than technical competence: the state wants someone accountable for the contract, not a skills test.
Sources and verification
How this was compiled
All 50 states were checked individually against the state's own occupational licensing directory, licensing board, or statute. Each state's source is linked in the tables above. Records whose sources were ambiguous were independently re-verified before publication.
Last verified July 2026 · 50 state records · Found an error? Report it and it will be corrected and logged on the corrections page.
See diesel mechanics pay and outlook, price a credential with the license cost estimator. Every state page for this trade is listed on the trades index.
Licensing requirements change between our verification sweeps. This page is informational only, so confirm with the board for your state before making decisions. Not legal advice.