Title: NGswin: N-Gram Swin Transformer for Efficient Single Image Super-Resolution. Abstract: In single image super-resolution (SISR), many deep learning-based methods suffer from intensive computational operations. In addition, while Swin Transformer-based methods such as SwinIR established state-of-the-art results, they still hold the problem of ignoring the broad regions when computing window self-attention (WSA) to reconstruct high-frequency information. In this paper, we propose the efficient NGswin network, which is the first attempt in history to introduce N-Gram to deep learning in images. For text analysis, N-Gram is a sequence of consecutive characters or words, but in an image, we define N-Gram as neighboring local windows (in WSA of Swin Transformer) which interact with each other by sliding-WSA. We propose N-Gram interaction, SCDP bottleneck, and a pooling-cascading mechanism, which enable the network to consider broad regions beneficial to recovering the degraded neighbor pixels. Moreover, we employ a hierarchical encoder with patch-merging, uni-Gram embedding, and a compact decoder to NGswin to enhance the network efficiency. Experimental results show that the proposed model achieves competitive performance in terms of PSNR and SSIM scores with fewer operations (Mult-Adds) compared to other methods.