Gabriel was a free agent after leaving Kilmarnock and had been training with Spurs.
"I'm pleased and excited with this move," the 23-year-old told BBC Sport about his switch to Waasland-Beveren on a one-and-a-half-year deal.
"This club and league is a good platform for me to develop my football further.
"It's a positive step in my career and I want to give my best to the club and fans."
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