The 19-year-old Australia Under-20 international joined Spurs in January 2011, having impressed on trial after leaving New South Wales Premier League outfit APIA Leichhardt Tigers.
His only senior appearance for Spurs came during last season's League Cup defeat to Stoke City at the Britannia Stadium, when he replaced Sandro as a 70th-minute substitute.
Confirming the move on Twitter, Luongo wrote: "Happy to have Things sorted at Ipswich.. It should be a good experience for me at this great club."
Luongo becomes the latest Spurs product to join Ipswich on a temporary deal, with the likes of Giovanni Dos Santos, Andros Townsend and Jake Livermore all spending time at the Championship club in recent seasons.
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