Qualcomm Inc. is expected to conduct a sweeping strategic review that will look at the possibility of a breakup, among other options, after an activist investor pushed for change at the chip maker.

Qualcomm, the world’s largest maker of chips used in mobile phones, may announce it is considering that and other options—including returning more cash to shareholders—when it reports fiscal third-quarter results Wednesday, according to people familiar with the matter. The company’s plans are in flux and there is no guarantee it...