Can I write off window decals for vehicle advertising?

The cost of window decals for vehicle advertising is deductible as a business expense if the vehicle is used for business purposes. This expense is considered part of advertising and marketing costs, which are generally deductible. However, if the vehicle is used for both personal and business purposes, only the portion of the cost attributable to business use is deductible. For example, if a vehicle is used 70% for business and 30% for personal use, then 70% of the decal cost can be deducted.