diff --git a/.changeset/rich-tips-yell.md b/.changeset/rich-tips-yell.md
new file mode 100644
index 000000000000..42f8392e375e
--- /dev/null
+++ b/.changeset/rich-tips-yell.md
@@ -0,0 +1,5 @@
+---
+"wrangler": patch
+---
+
+Prevents uploads with both cron triggers and smart placement enabled
diff --git a/packages/wrangler/src/__tests__/configuration.test.ts b/packages/wrangler/src/__tests__/configuration.test.ts
index d1c631ea49fa..3b2a87b4d382 100644
--- a/packages/wrangler/src/__tests__/configuration.test.ts
+++ b/packages/wrangler/src/__tests__/configuration.test.ts
@@ -960,7 +960,7 @@ describe("normalizeAndValidateConfig()", () => {
 				first_party_worker: true,
 				logpush: true,
 				placement: {
-					mode: "smart",
+					mode: "off",
 				},
 			};
 
@@ -4547,6 +4547,60 @@ describe("normalizeAndValidateConfig()", () => {
 			});
 		});
 
+		describe("[placement]", () => {
+			it("should error if both placement and triggers are configured", () => {
+				const { diagnostics } = normalizeAndValidateConfig(
+					{
+						triggers: {
+							crons: [1111],
+						},
+						placement: { mode: "smart" },
+					} as unknown as RawConfig,
+					undefined,
+					{ env: undefined }
+				);
+
+				expect(diagnostics.hasWarnings()).toBe(false);
+				expect(diagnostics.renderErrors()).toMatchInlineSnapshot(`
+			"Processing wrangler configuration:
+			  - You cannot configure both [triggers] and [placement] in your wrangler.toml. Placement is not supported with cron triggers."
+		`);
+			});
+			it("should not error if triggers are configured and placement is set off", () => {
+				const { diagnostics } = normalizeAndValidateConfig(
+					{
+						triggers: {
+							crons: [1111],
+						},
+						placement: { mode: "off" },
+					} as unknown as RawConfig,
+					undefined,
+					{ env: undefined }
+				);
+
+				expect(diagnostics.hasWarnings()).toBe(false);
+				expect(diagnostics.hasErrors()).toBe(false);
+			});
+			it("should not error if placement is configured and triggers is empty array", () => {
+				const expectedConfig: RawEnvironment = {
+					triggers: { crons: [] },
+					placement: {
+						mode: "smart",
+					},
+				};
+				const { config, diagnostics } = normalizeAndValidateConfig(
+					expectedConfig,
+					undefined,
+					{ env: undefined }
+				);
+
+				expect(config).toEqual(expect.objectContaining({ ...expectedConfig }));
+
+				expect(diagnostics.hasWarnings()).toBe(false);
+				expect(diagnostics.hasErrors()).toBe(false);
+			});
+		});
+
 		describe("(deprecated)", () => {
 			it("should remove and warn about deprecated properties", () => {
 				const environment: RawEnvironment = {
diff --git a/packages/wrangler/src/config/validation-helpers.ts b/packages/wrangler/src/config/validation-helpers.ts
index 0ecf579306c6..265079c89a2b 100644
--- a/packages/wrangler/src/config/validation-helpers.ts
+++ b/packages/wrangler/src/config/validation-helpers.ts
@@ -533,6 +533,27 @@ export const validateAdditionalProperties = (
 	return true;
 };
 
+/**
+ * Add a diagnostic error for any configurations that include both cron triggers and smart placement
+ */
+export const validateSmartPlacementConfig = (
+	diagnostics: Diagnostics,
+	placement: { mode: "off" | "smart" } | undefined,
+	triggers:
+		| {
+				crons: string[];
+		  }
+		| undefined
+): boolean => {
+	if (placement?.mode === "smart" && !!triggers?.crons?.length) {
+		diagnostics.errors.push(
+			`You cannot configure both [triggers] and [placement] in your wrangler.toml. Placement is not supported with cron triggers.`
+		);
+		return false;
+	}
+	return true;
+};
+
 /**
  * Get the names of the bindings collection in `value`.
  *
diff --git a/packages/wrangler/src/config/validation.ts b/packages/wrangler/src/config/validation.ts
index ff29abf48cbe..3c3c51405762 100644
--- a/packages/wrangler/src/config/validation.ts
+++ b/packages/wrangler/src/config/validation.ts
@@ -26,6 +26,7 @@ import {
 	appendEnvName,
 	getBindingNames,
 	isValidName,
+	validateSmartPlacementConfig,
 } from "./validation-helpers";
 import type { Config, DevConfig, RawConfig, RawDevConfig } from "./config";
 import type {
@@ -237,6 +238,8 @@ export function normalizeAndValidateConfig(
 		[...Object.keys(config), "env"]
 	);
 
+	validateSmartPlacementConfig(diagnostics, config.placement, config.triggers);
+
 	experimental(diagnostics, rawConfig, "assets");
 
 	return { config, diagnostics };