<p>Urban areas struggle with limited parking spaces due to the rising population within the cities’ fixed boundaries. Private parking spaces can be a better solution if shared efficiently and effectively. However, private parking owners will not share their resources for free and expect minimal overhead during the sharing process, as they are not professionals in this field. In this work, an online auction mechanism for private parking slot allocation (AMPSA) is designed to minimize overhead for private parking owners and encourage citizens to share their empty parking slots at any time. Users seeking parking, known as parkers, place bids to get parking near the desired location. The proposed allocation method schedules the non-overlapping parkers’ requests to available parking lots. Since the parkers may attempt to misrepresent their true value in bidding, the proposed pricing mechanism is designed to promote truthful bidding by offering suitable incentives. Simulation studies on generated datasets with 2,000 parkers and 200 parking owners, evaluated using profit, satisfaction ratio, number of winning parkers, and average waiting time, demonstrate the effectiveness of the proposed approach. AMPSA outperforms one-to-one space allocation by increasing owner profit, parker satisfaction, and the number of winning parkers by around 15%, 11%, and 28%, respectively, and simultaneously decreasing the average waiting time by nearly 12%.</p>