diff --git a/cli/CHANGELOG.md b/cli/CHANGELOG.md
index 10e38351f96e..d91ff59bf979 100644
--- a/cli/CHANGELOG.md
+++ b/cli/CHANGELOG.md
@@ -3,6 +3,10 @@
 
 _Released 11/5/2024 (PENDING)_
 
+**Features:**
+
+- Added ability to specify the default running browser in cypress config. Addresses [#6646](https://github.com/cypress-io/cypress/issues/6646).
+
 **Misc:**
 
 - Fixed a typo in CLI `global` option help text. Addresses [#30531](https://github.com/cypress-io/cypress/issues/30531).
diff --git a/cli/types/cypress.d.ts b/cli/types/cypress.d.ts
index f0f0c914b1c3..5a5be90b3868 100644
--- a/cli/types/cypress.d.ts
+++ b/cli/types/cypress.d.ts
@@ -3216,6 +3216,11 @@ declare namespace Cypress {
     setupNodeEvents: (on: PluginEvents, config: PluginConfigOptions) => Promise<PluginConfigOptions | void> | PluginConfigOptions | void
 
     indexHtmlFile: string
+
+    /**
+     * Set a default browser when user doesn't pass in "--browser".
+     */
+    defaultBrowser: string
   }
 
   interface EndToEndConfigOptions extends Omit<CoreConfigOptions, 'indexHtmlFile'> {
diff --git a/packages/data-context/src/DataContext.ts b/packages/data-context/src/DataContext.ts
index 895dc4d12e4e..9d1b9311d3ac 100644
--- a/packages/data-context/src/DataContext.ts
+++ b/packages/data-context/src/DataContext.ts
@@ -425,4 +425,8 @@ export class DataContext {
       this.#awaitingEmptyRequestCount.push(resolve)
     })
   }
+
+  setModeOptionsBrowser (browser: string) {
+    (this._modeOptions as Partial<AllModeOptions>).browser = browser
+  }
 }
diff --git a/packages/data-context/src/data/ProjectLifecycleManager.ts b/packages/data-context/src/data/ProjectLifecycleManager.ts
index c46d10b5161d..489c3d92bf29 100644
--- a/packages/data-context/src/data/ProjectLifecycleManager.ts
+++ b/packages/data-context/src/data/ProjectLifecycleManager.ts
@@ -308,10 +308,21 @@ export class ProjectLifecycleManager {
   /**
    * Sets the initial `activeBrowser` depending on these criteria, in order of preference:
    *  1. The value of `--browser` passed via CLI.
-   *  2. The last browser selected in `open` mode (by name and channel) for this project.
-   *  3. The first browser found.
+   *  2. The value of `defaultBrowser` in `cypress.config`.
+   *  3. The last browser selected in `open` mode (by name and channel) for this project.
+   *  4. The first browser found.
    */
   async setInitialActiveBrowser () {
+    const configBrowser = this.loadedFullConfig?.defaultBrowser
+
+    if (configBrowser) {
+      if (this.ctx.isRunMode && !this.ctx.modeOptions.isBrowserGivenByCli) {
+        this.ctx.setModeOptionsBrowser(configBrowser)
+      }
+
+      this.ctx.coreData.cliBrowser ??= configBrowser
+    }
+
     if (this.ctx.coreData.cliBrowser) {
       await this.setActiveBrowserByNameOrPath(this.ctx.coreData.cliBrowser)
 
diff --git a/packages/server/lib/modes/index.ts b/packages/server/lib/modes/index.ts
index c542b7d807b9..19376aa29c3e 100644
--- a/packages/server/lib/modes/index.ts
+++ b/packages/server/lib/modes/index.ts
@@ -18,6 +18,7 @@ export = (mode, options) => {
       quiet: false,
       morgan: false,
       report: true,
+      isBrowserGivenByCli: options.browser !== undefined,
     })
   }
 
diff --git a/packages/types/src/modeOptions.ts b/packages/types/src/modeOptions.ts
index f8ab17f81ec2..f12a99399f24 100644
--- a/packages/types/src/modeOptions.ts
+++ b/packages/types/src/modeOptions.ts
@@ -24,6 +24,7 @@ export interface RunModeOptions extends CommonModeOptions {
   parallel?: boolean | null
   ciBuildId?: string | null
   tag?: (string)[] | null
+  isBrowserGivenByCli: boolean
 }
 
 export type TestingType = 'e2e' | 'component'
diff --git a/system-tests/projects/config-defaultBrowser/cypress.config.js b/system-tests/projects/config-defaultBrowser/cypress.config.js
new file mode 100644
index 000000000000..20d060ec1140
--- /dev/null
+++ b/system-tests/projects/config-defaultBrowser/cypress.config.js
@@ -0,0 +1,8 @@
+const { defineConfig } = require('cypress')
+
+module.exports = defineConfig({
+  e2e: {
+    supportFile: false,
+  },
+  defaultBrowser: 'chrome',
+})
diff --git a/system-tests/projects/config-defaultBrowser/cypress/e2e/spec.cy.js b/system-tests/projects/config-defaultBrowser/cypress/e2e/spec.cy.js
new file mode 100644
index 000000000000..434d054dfaa1
--- /dev/null
+++ b/system-tests/projects/config-defaultBrowser/cypress/e2e/spec.cy.js
@@ -0,0 +1,3 @@
+it('works', () => {
+  expect(1).to.eq(1)
+})
diff --git a/system-tests/test/config_spec.js b/system-tests/test/config_spec.js
index b71c4a206a37..e139f9b382b3 100644
--- a/system-tests/test/config_spec.js
+++ b/system-tests/test/config_spec.js
@@ -243,4 +243,15 @@ describe('e2e config', () => {
       snapshot: true,
     })
   })
+
+  it('launches browser using config.defaultBrowser', async function () {
+    await Fixtures.scaffoldProject('config-defaultBrowser')
+
+    return systemTests.exec(this, {
+      project: 'config-defaultBrowser',
+      onStdout: (stdout) => {
+        expect(stdout).to.include('Browser:    Chrome')
+      },
+    })
+  })
 })