diff --git a/addon/-private/column-tree.js b/addon/-private/column-tree.js
index 9c31c0c03..06810e7d0 100644
--- a/addon/-private/column-tree.js
+++ b/addon/-private/column-tree.js
@@ -763,8 +763,14 @@ export default EmberObject.extend({
       return;
     }
 
+    let widthConstraint = get(this, 'widthConstraint');
     let isSlackModeEnabled = get(this, 'isSlackModeEnabled');
 
+    // For gte-container-slack, first try to expand columns to their maxWidth
+    if (widthConstraint === WIDTH_CONSTRAINT.GTE_CONTAINER_SLACK) {
+      this.expandColumnsToMax();
+    }
+
     if (isSlackModeEnabled) {
       this.updateSlackColumn();
     }
@@ -1177,4 +1183,80 @@ export default EmberObject.extend({
       this.token
     );
   },
+
+ /**
+   * Expands columns to their maxWidth when possible, while respecting container width
+   */
+  expandColumnsToMax() {
+    let containerWidth = this.getContainerWidth();
+    let leaves = get(this, 'root.leaves').filter(node => !get(node, 'isSlack'));
+
+    // Calculate total fixed width from columns with explicit width
+    let flexibleColumns = leaves.filter(node => !get(node, 'column.width'));
+    let totalFixedWidth = leaves.reduce((sum, node) => {
+      let columnWidth = get(node, 'column.width');
+      return sum + (columnWidth || 0);
+    }, 0);
+
+    let remainingWidth = containerWidth - totalFixedWidth;
+
+    // First pass: ensure all columns get at least their minWidth
+    let totalMinWidth = 0;
+    flexibleColumns.forEach(node => {
+      let minWidth = get(node, 'minWidth');
+      totalMinWidth += minWidth;
+    });
+
+    // If we don't have space for all minWidths, set all columns to minWidth
+    if (remainingWidth <= totalMinWidth) {
+      flexibleColumns.forEach(node => {
+        set(node, 'width', get(node, 'minWidth'));
+      });
+      return;
+    }
+
+    // Keep track of columns that still need width allocated
+    let columnsNeedingWidth = [...flexibleColumns];
+    let loopCount = 0;
+
+    // Continue redistributing width until all columns are satisfied or we hit guard
+    while (columnsNeedingWidth.length > 0 && loopCount < LOOP_COUNT_GUARD) {
+      let availableWidth = remainingWidth;
+      columnsNeedingWidth.forEach(node => {
+        availableWidth -= get(node, 'minWidth');
+      });
+
+      let equalExtraWidth = Math.floor(availableWidth / columnsNeedingWidth.length);
+      let columnsToRemove = [];
+
+      // Try to set each column to minWidth + equalExtraWidth
+      columnsNeedingWidth.forEach(node => {
+        let minWidth = get(node, 'minWidth');
+        let maxWidth = get(node, 'maxWidth');
+        let targetWidth = minWidth + equalExtraWidth;
+        let width = Math.min(Math.max(targetWidth, minWidth), maxWidth);
+
+        // If column hits a constraint, remove it from future calculations
+        if (width !== targetWidth) {
+          columnsToRemove.push(node);
+          remainingWidth -= width;
+        }
+
+        set(node, 'width', width);
+      });
+
+      // If no columns hit constraints, we're done
+      if (columnsToRemove.length === 0) {
+        break;
+      }
+
+      // Remove columns that hit constraints and continue redistributing
+      columnsToRemove.forEach(node => {
+        let index = columnsNeedingWidth.indexOf(node);
+        columnsNeedingWidth.splice(index, 1);
+      });
+
+      loopCount++;
+    }
+  },
 });
diff --git a/tests/helpers/generate-table.js b/tests/helpers/generate-table.js
index 7d61b3954..da2c86b87 100644
--- a/tests/helpers/generate-table.js
+++ b/tests/helpers/generate-table.js
@@ -11,7 +11,7 @@ import {
 export { configureTableGeneration, resetTableGenerationConfig, generateColumns, generateRows };
 
 const fullTable = hbs`
-  <div style="height: 500px;">
+  <div style="height: 500px; {{if this.containerWidth (concat 'width: ' this.containerWidth 'px;')}}">
     <EmberTable data-test-main-table as |t|>
       <EmberThead
         @api={{t}}
@@ -127,7 +127,7 @@ export function generateTableValues(
     footerRowCount = 0,
     columnCount = 10,
     columnOptions,
-
+    containerWidth,
     rowComponent = 'ember-tr',
 
     ...options
@@ -137,6 +137,7 @@ export function generateTableValues(
     testContext.set(property, options[property]);
   }
   testContext.set('rowComponent', rowComponent);
+  testContext.set('containerWidth', containerWidth);
 
   columns = columns || generateColumns(columnCount, columnOptions);
 
diff --git a/tests/integration/components/headers/main-test.js b/tests/integration/components/headers/main-test.js
index 158fe60bc..5407a32cc 100644
--- a/tests/integration/components/headers/main-test.js
+++ b/tests/integration/components/headers/main-test.js
@@ -437,6 +437,94 @@ module('Integration | header | main', function() {
       assert.equal(header.logicalWidth, 100, 'header is resized');
       assert.equal(slackHeader.logicalWidth, containerWidth - 100, 'slack column is expanded');
     });
+
+    test('expandColumnsToMax behavior in gte-container-slack mode', async function(assert) {
+      await generateTable(this, {
+        widthConstraint: 'gte-container-slack',
+        columnCount: 3,
+        columnOptions: {
+          minWidth: 50,
+          maxWidth: 200,
+        },
+        containerWidth: 600,
+      });
+
+      let containerWidth = table.logicalContainerWidth;
+      let header1 = table.headers.objectAt(0);
+      let header2 = table.headers.objectAt(1);
+      let header3 = table.headers.objectAt(2);
+      let slackHeader = table.slackHeaders.objectAt(0);
+
+      // Initially, columns should expand to fill container equally to 600
+      assert.equal(
+        header1.logicalWidth + header2.logicalWidth + header3.logicalWidth,
+        containerWidth,
+        'columns fill container width initially'
+      );
+
+      await generateTable(this, {
+        widthConstraint: 'gte-container-slack',
+        columnCount: 3,
+        columnOptions: {
+          minWidth: 50,
+        },
+        columns: [
+          { name: 'A', maxWidth: 50 },
+          { name: 'B', maxWidth: 200 }, // flexible
+          { name: 'C', maxWidth: 200 }, // flexible
+        ],
+        containerWidth: 600,
+      });
+
+      assert.equal(header1.logicalWidth, 50, 'first column respects maxWidth');
+
+      // Remaining space should be distributed between other columns up to maxWidth
+      let remainingWidth = containerWidth - 50;
+      let expectedWidth = Math.min(remainingWidth / 2, 200);
+      assert.equal(header2.logicalWidth, expectedWidth, 'second column expands within maxWidth');
+      assert.equal(header3.logicalWidth, expectedWidth, 'third column expands within maxWidth');
+
+      // If there's still space after maxWidth, it should go to slack
+      let totalColumnWidth = 50 + expectedWidth * 2;
+      if (totalColumnWidth < containerWidth) {
+        assert.ok(slackHeader.isRendered, 'slack column appears when space available');
+        assert.equal(
+          slackHeader.logicalWidth,
+          containerWidth - totalColumnWidth,
+          'slack column fills remaining space'
+        );
+      } else {
+        assert.notOk(slackHeader.isRendered, 'no slack column when columns fill width');
+      }
+
+      // Test flexible columns without explicit width
+      await generateTable(this, {
+        widthConstraint: 'gte-container-slack',
+        columnCount: 3,
+        columnOptions: {
+          minWidth: 50,
+        },
+        columns: [
+          { name: 'A', width: 100 },
+          { name: 'B', maxWidth: 200 },
+          { name: 'C', maxWidth: 200 },
+        ],
+        containerWidth: 600,
+      });
+
+      header1 = table.headers.objectAt(0);
+      header2 = table.headers.objectAt(1);
+      header3 = table.headers.objectAt(2);
+
+      // Fixed width column should maintain its width
+      assert.equal(header1.logicalWidth, 100, 'fixed width column maintains width');
+
+      // Flexible columns should share remaining space equally up to maxWidth
+      remainingWidth = containerWidth - 100;
+      expectedWidth = Math.min(remainingWidth / 2, 200);
+      assert.equal(header2.logicalWidth, expectedWidth, 'flexible column expands within maxWidth');
+      assert.equal(header3.logicalWidth, expectedWidth, 'flexible column expands within maxWidth');
+    });
   });
 
   componentModule('subcolumns', function() {