The Berkshire town, famous for being the location of The Office, has scooped the title two years in a row.
The Berkshire town retained its position based on the cost of housing, the ease of finding a job and employee satisfaction.
Slough was also said to have relatively high salaries and job vacancies.
Others in the top five were Gloucester, Cambridge, Reading and Guildford.
Average pay in Slough was said to be £29,500, compared with £24,000 in Gloucester, £30,400 in Cambridge, £30,000 in Reading and £27,500 in Guildford.
The average home values ranged from £239,000 in Gloucester to £593,000 in Guildford.
Slough, which also topped the list last year, was said to have more than 22,000 job vacancies - including work for project managers, customer service advisers and recruitment consultants.
The town is well known for the being the location of sitcom The Office, where Ricky Gervais starred as the cringe-inducing boss David Brent.
Amanda Stansell of Glassdoor said: "Slough is now firmly established as one of the best areas in the UK to work, because of its consistently high employee satisfaction and job opportunities relative to its population.
"It is also home to a huge range of employers. With plans now agreed for Heathrow's third runway and the new Crossrail in 2019, its growth potential is very positive."
"While several of the towns and cities highlighted in this report may be surprising, many are experiencing growing local economies, complete with a healthy dose of new job prospects and strong home affordability."