The warning comes after a number of people reported having packages pinched from their front door.
One Bearsden woman posted on a community social media page: “We had a parcel stolen from the front doorstep in broad daylight yesterday. Wanted to just flag so people can be vigilant.”
Another posted: “Some of the delivery drivers have just left my parcels on the front doorstep for all to see. They think taking a photo of it showing it has been delivered is enough.”
A police spokesperson said: “With an increase in online buying and parcel deliveries we would like to remind residents of East Dunbartonshire on the various measures that can be taken to prevent opportunist thiefs from stealing deliveries left when you are not at home.
"Obviously the best delivery is one where a resident is at home and is able to receive the goods.
"However failing this, we would ask residents to ensure communual areas are kept secured and that no strangers are provided access via intercom systems.
"Also consider investing in a video doorbell or CCTV.
"Most companys have provisions to allow the buyer to provide a place to leave parcels and the ability for deliveries to be tracked.
"Alternative delivery options to trusted neighbours or family members can be arranged if you know you are not going to be home.”
For more information and advice or to report a theft, contact police on 101.