The residential sales and letting specialists, based in Princes Square, were judged alongside other Harrogate agents, by a team of anonymous shoppers.
Branch manager Anthony Metcalfe said: "There is no shortage of quality estate agents across the Harrogate district so to scoop this award for a second time is a tremendous achievement. It is also a fitting way of marking our 20th anniversary year.
"Customer service is at the heart of the Linley & Simpson ethos, and the awards were an ideal opportunity to put our approach to the sternest scrutiny from independent mystery shoppers who hailed it as outstanding.
Robert McLean, a British Property Awards spokesman, said: Where an agent has been attributed with one of our awards, it is simply down to the fantastic customer service levels that have been demonstrated across a prolonged period of time.
"Agents who go that extra mile, and have outstanding levels of customer service, are rewarded with our accolade. It acts as a beacon to highlight these attributes to their local marketplace.
As providers of "the most comprehensive" awards in the property sector, the BPA compile a team of experts who judge all agencies which meet a basic criteria within a given town before judging which agency has performed outstandingly. Agencies are measured against a total of 25 criteria in order to get a balanced overview of their customer service levels.
Judging criteria is both comprehensive and detailed, exploring different mediums, scenarios and time periods to ensure agents have been rigorously and fairly judged.
This is the latest in a series of awards won recently by Linley & Simpson, an independent agency with 11 branches across North and West Yorkshire. Its sister offices in Wakefield and Horsforth, Leeds, also struck gold in their judging areas.
Previous national accolades have been awarded by judges in the Estate Agency of the Year awards, the Letting Agency of the Year awards, and the ESTAs - the Estate Agent and Letting Agent awards. It was also voted Estate Agency of the Year in the Yorkshire Residential Property Awards.