On 4 July 2012, Gylfi joined Tottenham Hotspur from 1899 Hoffenheim for a reported £8 million transfer fee.
He was the first signing for newly appointed Spurs manager André Villas-Boas.
On 18 July, he scored his first goal for the club in a friendly against Stevenage after coming on as a second-half substitute.
On 26 September, he scored his first competitive goal for the club in a League Cup third round tie away against Carlisle United, closing the scoring in a 3–0 win.

Brian McDermott confirmed Reading made three unsuccessful bids to bring Gylfi back to his former club during the January 2013 transfer window, including a club record offer on deadline day thought by BBC Sport to be around £10 million.
On 25 February, Gylfi scored his first Premier League goal for Tottenham, the second goal in a 3–2 win against West Ham United.
In the following match, a 2–1 North London derby win against Arsenal, he provided the assist for Gareth Bale.

In the 2013–14 season, Gylfi scored a brace in 2–0 win against Norwich City on 14 September 2013.
This win took Spurs up to second in the Premier League table.
Gylfi's momentum in the Tottenham team continued on 28 September 2013, as he scored in a 1–1 home draw against Chelsea.
On 4 July 2012, Gylfi joined Tottenham Hotspur from 1899 Hoffenheim for a reported £8 million transfer fee. He was the first signing for newly appointed Spurs manager André Villas-Boas. On 18 July, he scored his first goal for the club in a friendly against Stevenage after coming on as a second-half substitute. On 26 September, he scored his first competitive goal for the club in a League Cup third round tie away against Carlisle United, closing the scoring in a 3–0 win.
Brian McDermott confirmed Reading made three unsuccessful bids to bring Gylfi back to his former club during the January 2013 transfer window, including a club record offer on deadline day thought by BBC Sport to be around £10 million. On 25 February, Gylfi scored his first Premier League goal for Tottenham, the second goal in a 3–2 win against West Ham United. In the following match, a 2–1 North London derby win against Arsenal, he provided the assist for Gareth Bale.
In the 2013–14 season, Gylfi scored a brace in 2–0 win against Norwich City on 14 September 2013. This win took Spurs up to second in the Premier League table. Gylfi's momentum in the Tottenham team continued on 28 September 2013, as he scored in a 1–1 home draw against Chelsea.
Gylfi Sigurðsson