Agency: Ville et Village (villeetvillage.com)
Carolyn Grote visits each of the 200 villas in her collection; all are characteristic of their region (such as farmhouses in Provence). The staff is bilingual and offers local suggestions, from good cycling paths to off-the-radar restaurants.
Top property: Le Pavillon de Chasse
A 17th-century five-bedroom hunting lodge with pool, guesthouse, and a caretaker, on 650 acres in Provence's Luberon. $9,240/week.
Agency: Aqua Living (livinginternational.net)
Local staff can arrange anything from a massage therapist to a picnic lunch at a secluded beach near one of the company's stylish properties in Mykonos, Crete, Paros, Santorini, or Rhodes.
A large white house near Agrari Beach on Mykonos, with five bedrooms, an infinity pool, and multiple terraces with views of the Aegean. From $20,573/week.
Agency: The Best in Italy (thebestinitaly.com)
Countess Simonetta Brandolini d'Adda often stays in one of her company's 80 villas—mostly around Tuscany and Lake Como—when on vacation. Her well-connected owner friends can arrange private museum visits or concerts for clients.
Top property: Villa Pisana
The celeb-friendly eight-bedroom estate outside Pisa has its own laundress to attend to your riding gear. From $43,981/week.
Agency: Spain Select (spain-select.com)
A small collection of 65 villas ensures that manager Karin Wallis and her staff can regularly revisit each property. The best are spread across the Balearic Islands, Andalusia, and Majorca.
Top property: El Navio
A Modernist five-bedroom hilltop retreat in Cádiz, with three levels, floor-to-ceiling windows, indoor and outdoor pools, and a small gym. From $11,000/week.
Agency: RentVillas (rentvillas.com)
This 24-year-old agency has recently expanded beyond France and Italy to four regions in Turkey: the Aegean; Marmara, near Istanbul; the south; and central Anatolia. A personal travel advisor helps clients select their ideal house.
Top property: Villa Ilhan
The six-bedroom villa in Bodrum is a Mediterranean-style estate with a pool, on the grounds of a working farm. From $6,500/week.