diff --git a/README.md b/README.md
index 437a5bc..cfac396 100644
--- a/README.md
+++ b/README.md
@@ -100,6 +100,7 @@ outdoor_pm25_entity: sensor.outdoor_pm25
 | `hours_to_show` | number | No | 24 | Hours of history to display (1-168) |
 | `temperature_unit` | string | No | "auto" | Temperature unit: "auto" (detect from HA), "F" (Fahrenheit), or "C" (Celsius) |
 | `radon_unit` | string | No | "auto" | Radon unit: "auto" (detect from sensor), "pCi/L" (US), or "Bq/m3" (International) |
+| `order` | array | No | default | Custom display order for metrics (see [Sensor Order](#sensor-order)) |
 | `outdoor_co2_entity` | string | No | - | Outdoor CO2 sensor for comparison |
 | `outdoor_pm25_entity` | string | No | - | Outdoor PM2.5 sensor for comparison |
 | `outdoor_pm1_entity` | string | No | - | Outdoor PM1 sensor for comparison |
@@ -113,6 +114,27 @@ outdoor_pm25_entity: sensor.outdoor_pm25
 
 \* At least one sensor entity is required. Use any combination that fits your setup.
 
+### Sensor Order
+
+Customize which sensors come first on the card. Provide a list of metric names — any metric you don't list keeps its default position and stays visible.
+
+Valid metric names: `co`, `radon`, `co2`, `pm25`, `pm10`, `pm1`, `pm03`, `pm4`, `hcho`, `tvoc`, `nox`, `humidity`, `temperature`.
+
+```yaml
+type: custom:air-quality-card
+co2_entity: sensor.air_quality_co2
+humidity_entity: sensor.air_quality_humidity
+temperature_entity: sensor.air_quality_temp
+pm10_entity: sensor.air_quality_pm10
+pm25_entity: sensor.air_quality_pm25
+order:
+  - temperature
+  - humidity
+  - co2
+  - pm10
+  - pm25
+```
+
 ### Outdoor Sensors
 
 Configure outdoor sensor entities to see a **dashed comparison line** on each graph showing outdoor conditions alongside indoor readings. When outdoor sensors are configured:
diff --git a/air-quality-card.js b/air-quality-card.js
index 4e62067..c51df92 100644
--- a/air-quality-card.js
+++ b/air-quality-card.js
@@ -66,6 +66,28 @@ class AirQualityCard extends HTMLElement {
     this._updateStates();
   }
 
+  // Resolve the metric display order. User's `order` wins; anything they
+  // didn't list is appended in the default order so users never lose a
+  // configured metric by forgetting to mention it.
+  _getMetricOrder() {
+    const all = ['co', 'radon', 'co2', 'pm25', 'pm10', 'pm1', 'pm03', 'pm4', 'hcho', 'tvoc', 'nox', 'humidity', 'temperature'];
+    if (!Array.isArray(this._config.order) || !this._config.order.length) return all;
+    const valid = this._config.order.filter(m => all.includes(m));
+    const remaining = all.filter(m => !valid.includes(m));
+    return [...valid, ...remaining];
+  }
+
+  // Reorder graph cards via flexbox `order` rather than rebuilding the DOM —
+  // .graphs is already display:flex, so setting style.order on each container
+  // is enough to reflow them visually.
+  _applyMetricOrder() {
+    if (!Array.isArray(this._config.order) || !this._config.order.length) return;
+    this._getMetricOrder().forEach((metric, idx) => {
+      const container = this.shadowRoot.getElementById(`${metric}-graph-container`);
+      if (container) container.style.order = idx;
+    });
+  }
+
   getCardSize() {
     let size = 3; // Base size for header and recommendation
     if (this._config.co_entity) size += 1;
@@ -1113,6 +1135,8 @@ class AirQualityCard extends HTMLElement {
         </div>
       </ha-card>
     `;
+
+    this._applyMetricOrder();
   }
 
   _updateStates() {
@@ -1887,7 +1911,8 @@ if (LitElement && !customElements.get('air-quality-card-editor')) {
         hours_to_show: 'Graph History',
         temperature_unit: 'Temperature Unit',
         radon_unit: 'Radon Unit',
-        tvoc_unit: 'tVOC Measurement Type'
+        tvoc_unit: 'tVOC Measurement Type',
+        order: 'Sensor Order (list of metric names)'
       };
       return labels[schema.name] || schema.name;
     }
@@ -2000,6 +2025,7 @@ if (LitElement && !customElements.get('air-quality-card-editor')) {
           schema: [
             { name: 'air_quality_entity', selector: { entity: { domain: 'sensor' } } },
             { name: 'hours_to_show', selector: { number: { min: 1, max: 168, mode: 'box', unit_of_measurement: 'hours' } } },
+            { name: 'order', selector: { object: {} } },
             { name: 'temperature_unit', selector: { select: { options: [{ value: 'auto', label: 'Auto (from HA)' }, { value: 'F', label: 'Fahrenheit (°F)' }, { value: 'C', label: 'Celsius (°C)' }], mode: 'dropdown' } } },
             { name: 'radon_unit', selector: { select: { options: [{ value: 'auto', label: 'Auto (from sensor)' }, { value: 'pCi/L', label: 'pCi/L (US)' }, { value: 'Bq/m³', label: 'Bq/m³ (International)' }], mode: 'dropdown' } } },
             { name: 'tvoc_unit', selector: { select: { options: [{ value: 'auto', label: 'Auto-detect' }, { value: 'ppb', label: 'Absolute (ppb)' }, { value: 'index', label: 'VOC Index (Sensirion)' }], mode: 'dropdown' } } },
diff --git a/test.js b/test.js
index e33924f..d333aa6 100644
--- a/test.js
+++ b/test.js
@@ -492,6 +492,57 @@ try {
 }
 assert(configValid, 'radon_longterm_entity alone is valid config');
 
+// ============================================================
+// METRIC ORDERING (issue #19)
+// ============================================================
+
+section('Metric order — default');
+
+const defaultOrderCard = new CardClass();
+defaultOrderCard.setConfig({ co2_entity: 'sensor.co2' });
+const defaultOrder = defaultOrderCard._getMetricOrder();
+assert(defaultOrder[0] === 'co', 'default order: co first');
+assert(defaultOrder[defaultOrder.length - 1] === 'temperature', 'default order: temperature last');
+assert(defaultOrder.length === 13, 'default order: all 13 metrics');
+
+section('Metric order — user override');
+
+const reorderedCard = new CardClass();
+reorderedCard.setConfig({
+  co2_entity: 'sensor.co2',
+  order: ['temperature', 'humidity', 'co2', 'pm10', 'pm25']
+});
+const reordered = reorderedCard._getMetricOrder();
+assert(reordered[0] === 'temperature', 'user order: temperature first');
+assert(reordered[1] === 'humidity', 'user order: humidity second');
+assert(reordered[2] === 'co2', 'user order: co2 third');
+assert(reordered[3] === 'pm10', 'user order: pm10 fourth');
+assert(reordered[4] === 'pm25', 'user order: pm25 fifth');
+// Unmentioned metrics get appended in default order — user never loses a sensor
+assert(reordered.includes('radon'), 'unmentioned metrics still present');
+assert(reordered.length === 13, 'user order: total still 13');
+
+section('Metric order — invalid input');
+
+const badOrderCard = new CardClass();
+badOrderCard.setConfig({ co2_entity: 'sensor.co2', order: 'not an array' });
+const fallback = badOrderCard._getMetricOrder();
+assert(fallback[0] === 'co', 'non-array order falls back to defaults');
+
+const partialBadCard = new CardClass();
+partialBadCard.setConfig({
+  co2_entity: 'sensor.co2',
+  order: ['temperature', 'invalid_metric', 'co2']
+});
+const filtered = partialBadCard._getMetricOrder();
+assert(filtered.indexOf('temperature') === 0, 'invalid metrics are dropped, valid ones preserved');
+assert(filtered.indexOf('co2') === 1, 'invalid entries skipped in order');
+assert(!filtered.includes('invalid_metric'), 'invalid metric never appears');
+
+const emptyOrderCard = new CardClass();
+emptyOrderCard.setConfig({ co2_entity: 'sensor.co2', order: [] });
+assert(emptyOrderCard._getMetricOrder()[0] === 'co', 'empty array → default order');
+
 // ============================================================
 // CARD SIZE TESTS
 // ============================================================