diff --git a/addons/spreadsheet/static/src/pivot/pivot_model.js b/addons/spreadsheet/static/src/pivot/pivot_model.js
index 25b202c7b8b..379373d43f3 100644
--- a/addons/spreadsheet/static/src/pivot/pivot_model.js
+++ b/addons/spreadsheet/static/src/pivot/pivot_model.js
@@ -462,8 +462,9 @@ export class SpreadsheetPivotModel extends PivotModel {
      * @override
      */
     _getGroupValues(group, groupBys) {
-        return groupBys.map((groupBy) => {
-            const { field, aggregateOperator } = this.parseGroupField(groupBy);
+        return groupBys.map((gb) => {
+            const groupBy = this._normalize(gb);
+            const { field, aggregateOperator } = this.parseGroupField(gb);
             if (this._isDateField(field)) {
                 return pivotTimeAdapter(aggregateOperator).normalizeServerValue(
                     groupBy,
diff --git a/addons/web/static/src/views/pivot/pivot_model.js b/addons/web/static/src/views/pivot/pivot_model.js
index 475ce5bb6da..b8ad33606c3 100644
--- a/addons/web/static/src/views/pivot/pivot_model.js
+++ b/addons/web/static/src/views/pivot/pivot_model.js
@@ -933,6 +933,19 @@ export class PivotModel extends Model {
             return values[0];
         }
     }
+    /**
+     * @protected
+     * @param {string[]} rowGroupBy
+     * @param {string[]} colGroupBy
+     * @returns {string[]}
+     */
+    _getGroupBySpecs(rowGroupBy, colGroupBy) {
+        const set = rowGroupBy.concat(colGroupBy).reduce((acc, gb) => {
+            acc.add(this._normalize(gb));
+            return acc;
+        }, new Set());
+        return [...set];
+    }
     /**
      * Returns a domain representation of a group
      *
@@ -959,7 +972,8 @@ export class PivotModel extends Model {
      * @returns {string[]}
      */
     _getGroupLabels(group, groupBys, config) {
-        return groupBys.map((groupBy) => {
+        return groupBys.map((gb) => {
+            const groupBy = this._normalize(gb);
             return this._sanitizeLabel(group[groupBy], groupBy, config);
         });
     }
@@ -977,7 +991,7 @@ export class PivotModel extends Model {
     async _getGroupSubdivision(group, rowGroupBy, colGroupBy, config) {
         const groupDomain = this._getGroupDomain(group, config);
         const measureSpecs = this._getMeasureSpecs(config);
-        const groupBy = rowGroupBy.concat(colGroupBy);
+        const groupBy = this._getGroupBySpecs(rowGroupBy, colGroupBy);
         const kwargs = { lazy: false, context: this.searchParams.context };
         const subGroups = await this.orm.readGroup(
             config.metaData.resModel,
@@ -1002,7 +1016,8 @@ export class PivotModel extends Model {
      * @returns {Array}
      */
     _getGroupValues(group, groupBys) {
-        return groupBys.map((groupBy) => {
+        return groupBys.map((gb) => {
+            const groupBy = this._normalize(gb);
             return this._sanitizeValue(group[groupBy]);
         });
     }
@@ -1411,6 +1426,20 @@ export class PivotModel extends Model {
         this.data = config.data;
         this.metaData = config.metaData;
     }
+    /**
+     * @protected
+     * @param {string} gb
+     * @returns {string}
+     */
+    _normalize(gb) {
+        const [fieldName, interval] = gb.split(":");
+        const field = this.metaData.fields[fieldName];
+        if (["date", "datetime"].includes(field.type)) {
+            return `${fieldName}:${interval || "month"}`;
+        } else {
+            return fieldName;
+        }
+    }
     /**
      * Extract the information in the read_group results (groupSubdivisions)
      * and develop this.data.rowGroupTree, colGroupTree, measurements, counts, and
diff --git a/addons/web/static/tests/views/pivot_view_tests.js b/addons/web/static/tests/views/pivot_view_tests.js
index 9847b304245..33b973b80ea 100644
--- a/addons/web/static/tests/views/pivot_view_tests.js
+++ b/addons/web/static/tests/views/pivot_view_tests.js
@@ -5753,4 +5753,24 @@ QUnit.module("Views", (hooks) => {
         assert.strictEqual(columns[1].innerText, "aaa");
         assert.strictEqual(columns[2].innerText, "bbb");
     });
+
+    QUnit.test("avoid duplicates in read_group parameter 'groupby'", async function (assert) {
+        await makeView({
+            type: "pivot",
+            resModel: "partner",
+            serverData,
+            arch: `
+                    <pivot sample="1">
+                        <field name="date" type="row"/>
+                        <field name="date" type="col" interval="month"/>
+                    </pivot>
+                `,
+            mockRPC(_, { method, kwargs }) {
+                if (method === "read_group") {
+                    assert.step(JSON.stringify(kwargs.groupby));
+                }
+            },
+        });
+        assert.verifySteps([`[]`, `["date:month"]`, `["date:month"]`, `["date:month"]`]);
+    });
 });