One of two boys who went missing from school in Sydney's southwest has returned home but police continue to search for his friend.

Jaydan Patterson, 13, and Tyler Rolani, 11, were last seen leaving their school at Warwick Farm about 10.35am (AEDT) on Monday.

Police were seriously concerned for their welfare as they both had intellectual disabilities and could be easily disoriented.

Tyler had since returned home to his family in Macquarie Fields and was safe and well.

They said they were following a number of inquiries to locate his friend Jaydan.

He has dark hair and freckles and is believed to be wearing three-quarter length shorts, a dark coloured collared shirt and black runners.

Anyone with information about his whereabouts should immediately call triple-zero.