The broadcasting watchdog said that the 17 July episode of the ITV dating show was hit with a whopping 2,630 complaints over “alleged misogynistic and bullying behaviour by some contestants in the villa".
I'm A Celeb was hot on its heels with 1,890 complaints.
The jungle show was at the centre of controversy this year over former health secretary Matt Hancock becoming a camper.
Ofcom received a flurry of complaints when the series aired from 6 to 27 November, and said it was because viewers "objected" to the politician being a contestant.
However, a message on Ofcom's site said: "We carefully assessed complaints about both of these programmes and found that neither warranted further investigation under our rules."
The watchdog said the complaints about Love Island - which was hosted by Laura Whitmore - were assessed and the conclusion was that it "did not warrant formal investigation because of how this behaviour was put into context on the programme".
Commenting on the I'm A Celebrity complaints, they said an almost identical number of people objected to what they saw as "negative treatment" of Hancock.
They also noted that there is no ban on any particular person taking part in programmes.
Other shows that made the top 10 complained about shows of the year included Friday Night Live, Good Morning Britain, Jeremy Vine and Sky News.
The FIFA World Cup Final match on 18 December was ninth in the list, with 605 complaints that "related to politicised comments from Gary Neville".
The figures were recorded from 1 January to 19 December this year.
Watch: ITV defends Laura Whitmore after hundreds of Ofcom complaints