Do contractors have to follow the JTR?

No, contractors do not have to follow JTR directly as a personnel regulation, because JTR stands for Joint Travel Regulations which apply to Uniformed Services members and DoD civilian employees, not private contractor employees. Contractors are governed by Federal Acquisition Regulation FAR and their contract terms. However, many DoD contracts include a travel clause that says contractor travel costs will be reimbursed only to the extent that they are allowable and in accordance with JTR or Federal Travel Regulation FTR. In that case, contractor must follow JTR per diem rates, economy airfare requirement, 75 dollar receipt rule, and lodging limits to get reimbursed, otherwise government will not pay travel costs. For example, contract may state travel shall be reimbursed in accordance with JTR, meaning contractor cannot bill business class airfare or luxury hotel beyond per diem. If contract does not reference JTR, contractor follows company travel policy and FAR Part 31 cost principles which require travel costs to be reasonable. Contractor is not required to use Defense Travel System DTS or obtain military travel orders. So direct answer is contractors do not have to follow JTR as law, but they may have to follow JTR rates and rules if contract says so for reimbursement purposes. Government employees should check contract travel clause before approving contractor travel. So JTR does not apply to contractors as persons, but may apply as cost limitation.