diff --git a/src/lib/components/AddConnectionModal.svelte b/src/lib/components/AddConnectionModal.svelte
index 16616fc247..68eb96b70f 100644
--- a/src/lib/components/AddConnectionModal.svelte
+++ b/src/lib/components/AddConnectionModal.svelte
@@ -140,10 +140,19 @@
 	};
 
 	const addModelHandler = () => {
-		if (modelId) {
-			modelIds = [...modelIds, modelId];
-			modelId = '';
+		const newModelId = modelId.trim();
+
+		if (!newModelId) {
+			return;
 		}
+
+		if (modelIds.includes(newModelId)) {
+			toast.error($i18n.t('Model ID is already added'));
+			return;
+		}
+
+		modelIds = [...modelIds, newModelId];
+		modelId = '';
 	};
 
 	const submitHandler = async () => {
@@ -245,7 +254,7 @@
 			passthroughParams = Array.isArray(connection.config?.passthrough_params)
 				? connection.config.passthrough_params.join(', ')
 				: (connection.config?.passthrough_params ?? '');
-			modelIds = connection.config?.model_ids ?? [];
+			modelIds = [...new Set(connection.config?.model_ids ?? [])];
 
 			if (ollama) {
 				connectionType = connection.config?.connection_type ?? 'local';
diff --git a/src/lib/components/admin/Settings/Evaluations/ArenaModelModal.svelte b/src/lib/components/admin/Settings/Evaluations/ArenaModelModal.svelte
index ec8d997233..7f2667e35d 100644
--- a/src/lib/components/admin/Settings/Evaluations/ArenaModelModal.svelte
+++ b/src/lib/components/admin/Settings/Evaluations/ArenaModelModal.svelte
@@ -54,10 +54,10 @@
 	let showDeleteConfirmDialog = false;
 
 	const addModelHandler = () => {
-		if (selectedModelId) {
+		if (selectedModelId && !modelIds.includes(selectedModelId)) {
 			modelIds = [...modelIds, selectedModelId];
-			selectedModelId = '';
 		}
+		selectedModelId = '';
 	};
 
 	const submitHandler = () => {
@@ -111,7 +111,7 @@
 			id = model.id;
 			profileImageUrl = model.meta.profile_image_url;
 			description = model.meta.description;
-			modelIds = model.meta.model_ids || [];
+			modelIds = [...new Set(model.meta.model_ids || [])];
 			filterMode = model.meta?.filter_mode ?? 'include';
 			accessGrants = model.meta.access_grants ?? [];
 		}
@@ -362,7 +362,7 @@
 								bind:value={selectedModelId}
 							>
 								<option value="">{$i18n.t('Select a model')}</option>
-								{#each $models.filter((m) => m?.owned_by !== 'arena') as model}
+								{#each $models.filter((m) => m?.owned_by !== 'arena' && !modelIds.includes(m?.id)) as model}
 									<option value={model.id} class="bg-gray-50 dark:bg-gray-700">{model.name}</option>
 								{/each}
 							</select>
diff --git a/src/lib/i18n/locales/en-US/translation.json b/src/lib/i18n/locales/en-US/translation.json
index da7da2fb01..1f15676d7f 100644
--- a/src/lib/i18n/locales/en-US/translation.json
+++ b/src/lib/i18n/locales/en-US/translation.json
@@ -1700,6 +1700,7 @@
 	"Model filesystem path detected. Model shortname is required for update, cannot continue.": "",
 	"Model Filtering": "",
 	"Model ID": "",
+	"Model ID is already added": "",
 	"Model ID is required.": "",
 	"Model IDs": "",
 	"Model is now private": "",