The best way to quiet a neighbor's barking dog is usually to approach the neighbors and ask them to find a solution, according to WTOP. If the problem persists, try contacting the landlord, housing association or animal control.
Persistent dog barking may be caused by anxiety or other underlying issues that the owner needs to treat, so there may not be much neighbors can do to quiet the dog, as reported by WTOP. If your neighbor seems receptive to fixing the problem but is unsure of how to proceed, consider suggesting calming supplements or specific management changes.
If the owner refuses to try to correct the problem and you live in an apartment complex, contact your landlord or property management company before you escalate to contacting authorities, as suggested by Apartments.com. This may also work if you live in separate homes but can contact your neighbor's landlord.
If you are concerned for the dog's health or safety, such as in situations where the dog is outside in extremely hot or cold weather without adequate shelter, contact animal control immediately, suggests WTOP. Otherwise, nuisance laws vary depending on the area, but most places have laws against noisy dogs. Call your city's animal control department or police non-emergency line for more specific advice.