Fear and anxiety disorders are among the most prevalent welfare problems in companion dogs, affecting an estimated 20-40% of the population. Noise sensitivity (fireworks, thunderstorms) affects 25-50% of dogs in survey studies; separation anxiety affects 15-20%. These conditions cause significant suffering: affected dogs show physiological stress responses (elevated cortisol, heart rate), destructive behaviour, vocalisation, self-injury, and chronic hypervigilance. Welfare compromise is often unrecognised by owners who interpret fear behaviours as naughtiness or dominance rather than anxiety. Evidence-based treatment includes systematic desensitisation and counter-conditioning, environmental management (safe spaces, sound insulation), and pharmacological support (fluoxetine, clomipramine, imepitoin, situational alprazolam). Research demonstrates that fear and anxiety have a genetic component, informing breeding selection against high-anxiety lines. Early socialisation and positive training during the critical period remain the most effective preventive strategies. Owner education on recognition, force-free training, and prompt veterinary help-seeking are welfare-positive priorities.