Recent monocular 3D shape reconstruction methods have shown promising zero-shot results on object-segmented images without any occlusions. However, their effectiveness is significantly compromised in real-world settings, due to imperfect object segmentation by off-the-shelf models and the prevalence of occlusions. To address these issues, we propose a unified regression model that integrates segmentation and reconstruction, specifically designed for occlusion-aware 3D shape reconstruction. To facilitate its reconstruction in the wild, we also introduce a scalable data synthesis pipeline that simulates a wide range of variations in objects, occluders, and backgrounds. Training on our synthesized data enables the proposed model to achieve state-of-the-art zero-shot results on real-world images, using significantly fewer model parameters than competing approaches. Our code and data would be publicly available.