The Finn returned to formula in 2012 after a two-year absence and has enjoyed an impressive debut campaign with the Enstone outfit.
Only once has Raikkonen failed to finish among the points in 17 attempts with his new team, and the former world champion has admitted his surprise at how well his comeback has gone.
"I think my return to Formula 1 has gone pretty well and the team has done a very good job all year so far," the 33-year-old said.
"To be honest, I didn't expect to be fighting for the Drivers' Championship this season when you look at where the team was in 2011, so it has been great to be on the podium so many times and to score points on a regular basis."
Raikkonen added that his decision to remain with Lotus was a simple one, with optimism already high for their prospects together next year.
"I feel very comfortable with Lotus F1 Team and we share the same philosophy of racing," he said.
"Continuing with the team was an obvious choice for me and I'm looking forward to making another step forward together next year."
Raikkonen currently sits third in the Drivers' Championship with 173 points.