HONG KONG—The new iPhone that Apple Inc. is expected to unveil this year is likely to have a larger display than its current models have, with the company ordering bigger screens from its Asian suppliers, people familiar with the matter said.

The new screens measure at least 4 inches diagonally, the people said, compared with 3.5 inches on Apple's latest model, the iPhone 4S. Production is set to begin next month, the people said. Analysts have predicted that the next iPhone will come out in the fall.

Apple...