Tilly Smith, from Oxshott, Surrey, was holidaying with her parents and seven-year-old sister on Maikhao beach in Phuket, Thailand, when the tide rushed out.
Her parents alerted the other holidaymakers and staff at their hotel, which was quickly evacuated. The wave crashed a few minutes later, but no one on the beach was killed or seriously injured.
In an interview with the Sun, Tilly gave the credit to her geography teacher, Andrew Kearney, at Oxshott's Danes Hill Prep School.
She said "Last term Mr Kearney taught us about earthquakes and how they can cause tsunamis.
"I was on the beach and the water started to go funny. There were bubbles and the tide went out all of a sudden.
"I recognised what was happening and had a feeling there was going to be a tsunami. I told mummy."