The awards which were presented virtually, also saw Patty & Bun pick up best burger, while Nandos won most-loved chain.
The awards were judged by a celebrity panel of judges, including Maya Jama, Vogue Williams, reigning Celebrity MasterChef champ Riyadh Khalaf and Deliveroo's CEO Will Shu.
Judges praised 'The Athenian' for their support of Deliveroo's United Kingdom National Health Service (NHS) initiative to donate over 2,500 meals to NHS heroes during the Covid-19 pandemic.
On top of this, the Greek restaurant gave a 50% discount available to all NHS staff and also launched a weekly parcel for their employees to ensure they had all the necessities during the pandemic.
"From showing an amazing commitment to delivery throughout the pandemic, keeping all staff employed throughout the peak of lockdown, running virtual cook-a-long's on Instagram during lockdown and investing in delivery-only, The Athenian has gone over and above this year to support the community," a Deliveroo spokeperson told Femail.
More than 400,000 votes were cast over the course of the competition.
"This year has undoubtedly been one of the most challenging years the restaurant sector has ever faced. Yet in the face of huge uncertainty, we have been inspired by the way restaurants across the UK and Ireland have stepped up and gone the extra mile to support their local communities, while working tirelessly to keep their own businesses going," Will Shu said.
Efthymios and Neofytos, two Londoners born and raised in Athens and Cyprus, launched 'The Athenian' at the end of 2014, as a small street food venture offering freshly made souvlaki prepared in the healthiest, most authentic way possible.
"At The Athenian we start making our souvlaki by grilling tender pieces of chicken, pork or tasty Talagani cheese (think halloumi with a more refined texture and minty undertone) marinated in Greek herbs, before wrapping them in a soft, handmade pita and adding freshly chopped red onions, tomatoes, lettuce and parsley. We top things off with a choice of our perfected homemade dips: tyrokafteri (spicy feta and red pepper), tzatziki (cucumber, yogurt and garlic) or our original Souvlaki Sauce, a top secret recipe, designed to lend a subtle sweetness to the flavourings."