diff --git a/sao/CHANGELOG b/sao/CHANGELOG
index 338d6f8667..d2e0cc6b96 100644
--- a/sao/CHANGELOG
+++ b/sao/CHANGELOG
@@ -1,3 +1,4 @@
+* Allow column resizing
 * Add simple chat widget on sidebar
 * Support color as type of icon and image
 * Support color widget on form view
diff --git a/sao/src/sao.less b/sao/src/sao.less
index 71286d226d..ca74753698 100644
--- a/sao/src/sao.less
+++ b/sao/src/sao.less
@@ -708,6 +708,15 @@ img.icon {
     display: flex;
     flex-direction: column;
     min-height: 0;
+
+    .tree-dragged-image {
+        display: block;
+        height: 0;
+        left: 0;
+        position: absolute;
+        top: 0;
+        width: 0;
+    }
 }
 
 .wizard-form {
@@ -724,6 +733,11 @@ img.icon {
     > table.tree {
         width: 100%;
         table-layout: fixed;
+        border: 1px solid transparent;
+
+        &.table-bordered {
+            border-color: @table-border-color;
+        }
 
         col.selection-state, col.favorite, col.tree-menu {
             width: 30px;
@@ -749,15 +763,37 @@ img.icon {
             }
         }
         > thead > tr > th {
-            > label.sortable {
-                cursor: pointer;
+            position: relative;
+            padding: 5px;
+
+            > label {
+                display: inline-block;
+                overflow: hidden;
+                text-overflow: ellipsis;
+                white-space: nowrap;
+                margin: 0;
+
+                &.sortable {
+                    cursor: pointer;
+                }
             }
+
+            > div.resizer {
+                z-index: 1;
+                position: absolute;
+                top: 0;
+                inset-inline-end: -5px;
+                width: 2px;
+                height: 100%;
+                cursor: ew-resize;
+                padding: 0 4px;
+                background-color: transparent;
+            }
+
             &.tree-menu {
                 cursor: pointer;
                 overflow: visible;
             }
-            overflow: hidden;
-            text-overflow: ellipsis;
             text-align: center;
             &.char, &.text, &.many2one, &.one2one, &.date, &.time, &.selection,
             &.reference, &.url, &.email, &.callto, &.sip {
@@ -775,8 +811,15 @@ img.icon {
             z-index: 100;
 
             th {
+                border: 1px solid transparent;
+                border-bottom: 2px solid @table-border-color;
                 background-color: @body-bg;
             }
+
+            &:hover th {
+                border: 1px solid @table-border-color;
+                border-bottom-width: 2px;
+            }
         }
         > tfoot > tr {
             bottom: 0;
@@ -920,6 +963,26 @@ img.icon {
         padding-top: 0;
         padding-bottom: 0;
     }
+
+    > table.table-bordered {
+        border: 1px solid @table-border-color;
+        > thead,
+        > tbody,
+        > tfoot {
+            > tr:first-child {
+                > th,
+                > td {
+                    border: 1px solid @table-border-color;
+                }
+            }
+        }
+        > thead > tr:first-child {
+            > th,
+            > td {
+                border-bottom-width: 2px;
+            }
+        }
+    }
 }
 
 .form, .board {
diff --git a/sao/src/screen.js b/sao/src/screen.js
index 183d6bd735..69d5b7c6e9 100644
--- a/sao/src/screen.js
+++ b/sao/src/screen.js
@@ -2219,6 +2219,7 @@
                 } else if (~['tree', 'list-form'].indexOf(view.view_type)) {
                     var paths;
                     if (view.view_type == 'tree') {
+                        view.save_width();
                         paths = view.get_expanded_paths();
                     } else {
                         paths = [];
@@ -2345,5 +2346,6 @@
             });
         }
     });
+    Sao.Screen.tree_column_width = {};
     Sao.Screen.tree_column_optional = {};
 }());
diff --git a/sao/src/view/tree.js b/sao/src/view/tree.js
index 7d5a3ac732..17ff68ee70 100644
--- a/sao/src/view/tree.js
+++ b/sao/src/view/tree.js
@@ -15,6 +15,35 @@
         });
     }
 
+    // circumvent https://bugzilla.mozilla.org/show_bug.cgi?id=505521
+    let dragoverFixAdded = false;
+    let lastWindowDragEvent = null;
+    const fillEventScreenPosition = (e) => {
+        e.screenPosition = {
+            x: e.screenX,
+            y: e.screenY,
+        };
+
+        if (!navigator.userAgent.search("Firefox")) {
+            return;
+        }
+
+        if (!dragoverFixAdded) {
+            window.addEventListener('dragover', (e) => {
+                lastWindowDragEvent = e;
+            });
+            dragoverFixAdded = true;
+        }
+
+        if (lastWindowDragEvent &&
+            (e.timeStamp - lastWindowDragEvent.timeStamp) < 100) {
+            e.screenPosition = {
+                x: lastWindowDragEvent.screenX,
+                y: lastWindowDragEvent.screenY,
+            };
+        }
+    }
+
     Sao.View.TreeXMLViewParser = Sao.class_(Sao.View.XMLViewParser, {
         _parse_tree: function(node, attributes) {
             for (const child of node.childNodes) {
@@ -118,6 +147,9 @@
             this.treeview = jQuery('<div/>', {
                 'class': 'treeview responsive'
             }).appendTo(this.el);
+            this.dragged_image= jQuery('<span/>', {
+                'class': 'tree-dragged-image',
+            }).html('&nbsp;').appendTo(this.el);
 
             // Synchronize both scrollbars
             this.treeview.scroll(() => {
@@ -189,6 +221,7 @@
                     });
             }
 
+            let idx = 2;
             for (const column of this.columns) {
                 col = jQuery('<col/>', {
                     'class': column.attributes.widget,
@@ -197,6 +230,7 @@
                     'class': column.attributes.widget,
                 });
                 th.uniqueId();
+                th.get(0).dataset.column = idx;
                 var label = jQuery('<label/>')
                     .text(column.attributes.string)
                     .attr('title', column.attributes.string);
@@ -221,6 +255,52 @@
                     label.addClass('sortable');
                 }
                 tr.append(th.append(label));
+                let resizer = jQuery('<div/>', {
+                    'class': 'resizer',
+                    'draggable': true,
+                }).appendTo(th);
+                resizer.on('dragstart', (event) => {
+                    let th = event.target.parentNode;
+                    let headers = th.parentNode.childNodes;
+                    let cols = this.colgroup[0].childNodes;
+                    for (let i = 0; i < headers.length; i++) {
+                        let header = headers[i];
+                        let col = cols[i];
+                        if (header == th) {
+                            break;
+                        }
+                        if (col.style.display != 'none') {
+                            col.style.width = `${header.offsetWidth}px`;
+                        }
+                    }
+                    th.dataset.startPosition = event.screenX;
+                    th.dataset.originalWidth = th.offsetWidth;
+
+                    this.table.addClass('table-bordered');
+                    event.originalEvent.dataTransfer.setDragImage(
+                        this.dragged_image.get(0), 0, 0);
+                });
+                // column_widths is used as a global for the callback of the
+                // drag event so that when the setTimeout callback is triggered
+                // the latest value of the width is used
+                let column_widths = {};
+                resizer.on('drag', (event) => {
+                    fillEventScreenPosition(event);
+                    let resized_th = event.target.parentNode;
+                    let col = this.colgroup[0].childNodes[resized_th.dataset.column];
+                    let width_offset = (event.screenPosition.x -
+                        resized_th.dataset.startPosition);
+                    if (Sao.i18n.rtl) {
+                        width_offset *= -1;
+                    }
+                    let width = Number(resized_th.dataset.originalWidth) + width_offset;
+                    column_widths[resized_th] = width;
+                    setTimeout(() => {
+                        let width = column_widths[resized_th];
+                        col.style.width = `${width}px`;
+                    });
+                });
+
                 column.header = th;
                 column.col = col;
 
@@ -238,7 +318,20 @@
                     sum_row.append(total_cell);
                     column.footers.push(total_cell);
                 }
+                idx += 1;
             }
+
+            this.table.on('dragover', (event) => {
+                // This is necessary so that the 'drop' event is processed
+                event.preventDefault();
+            });
+            this.table.on('drop', (event) => {
+                event.preventDefault();
+                if (!this.editable) {
+                    this.table.removeClass('table-bordered');
+                }
+            });
+
             this.tbody = jQuery('<tbody/>');
             this.table.append(this.tbody);
 
@@ -352,6 +445,36 @@
             }
             Sao.Screen.tree_column_optional[this.view_id] = fields;
         },
+        save_width: function() {
+            var widths = {};
+            for (let column of this.columns) {
+                if (!column.get_visible() || !column.attributes.name ||
+                    column instanceof Sao.View.Tree.ButtonColumn) {
+                    continue;
+                }
+
+                // Use the DOM element to retrieve the exact style set
+                var width = column.col[0].style.width;
+                if (width.endsWith('px')) {
+                    widths[column.attributes.name] = Number(width.slice(0, -2));
+                }
+            }
+
+            var model_name = this.screen.model_name;
+            var TreeWidth = new Sao.Model('ir.ui.view_tree_width');
+            TreeWidth.execute(
+                'set_width',
+                [model_name, widths],
+                {});
+            if (Object.prototype.hasOwnProperty.call(
+                    Sao.Screen.tree_column_width, model_name)) {
+                Object.assign(
+                    Sao.Screen.tree_column_width[model_name],
+                    widths);
+            } else {
+                Sao.Screen.tree_column_width[model_name] = widths;
+            }
+        },
         reset: function() {
             this.display_size = null;
         },
@@ -826,6 +949,8 @@
             domain = inversion.simplify(domain);
             var decoder = new Sao.PYSON.Decoder(this.screen.context);
             var min_width = [];
+            let tree_column_width = (
+                Sao.Screen.tree_column_width[this.screen.model_name] || {});
             var tree_column_optional = (
                 Sao.Screen.tree_column_optional[this.view_id] || {});
             for (const column of this.columns) {
@@ -875,7 +1000,11 @@
                     !column.col.hasClass('selection-state') &&
                     !column.col.hasClass('favorite')) {
                     var width, c_width;
-                    if (column.attributes.width) {
+                    width = tree_column_width[name];
+                    if (width) {
+                        c_width = width;
+                        min_width.push(`${width}px`);
+                    } else if (column.attributes.width) {
                         width = c_width = column.attributes.width;
                         min_width.push(width + 'px');
                     } else {