Serero joined Ajax from feeder club Ajax Cape Town in 2011 and has gone on to make 61 appearances in that time, scoring eight goals.
The South African's deal was due to expire at the end of the upcoming season, but the Dutch champions confirmed on Tuesday that they had extended the terms of his contract by a further two years.
"I am very happy with this contract extension," Serero told Ajax's official website.
"I think it's wonderful to play here. Ajax play football in Europe and have given me a chance which I am extremely grateful for.
"It was not a difficult decision to renew my contract.
"The club means a lot to me and I want to trust that I get to pay that back on the field."
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