Plant cell walls are dynamic structures that show changes in composition and configuration depending on the developmental stage, biotic, and abiotic factors. Therefore, it is necessary to have tools for visualizing the components of the cell wall in situ at any stage. Here, we describe how specific monoclonal antibodies can be used to examine the distribution of plant cell wall glycan epitopes at the whole plant, tissue, cell, and subcellular levels. Understanding the basic cell wall structure is essential for devising efficient strategies to convert cell walls to fermentable sugars for ethanol production.