diff --git a/README.md b/README.md
index 9a308c7..cbfb309 100644
--- a/README.md
+++ b/README.md
@@ -60,6 +60,7 @@ Check the default configuration with all the options [here](./internal/config/de
 | `--host`                |       | Proxy host, overrides config                                                   |
 | `--port`                | `-p`  | Proxy port, overrides config                                                   |
 | `--project`             | `-P`  | Project name to open directly, or `tmp` for a temporary session                |
+| `--upstream-proxy`      |       | Upstream proxy URL, overrides config (e.g. `http://user:pass@host:8888`)       |
 | `--version`             | `-v`  | Print version and exit                                                         |
 | `--add-default-plugins` |       | Add the default plugins to your plugins dir and exit                           |
 
diff --git a/cmd/spilltea/main.go b/cmd/spilltea/main.go
index 2acd629..b0860ad 100644
--- a/cmd/spilltea/main.go
+++ b/cmd/spilltea/main.go
@@ -7,11 +7,11 @@ import (
 	"path/filepath"
 
 	tea "charm.land/bubbletea/v2"
+	spilltea "github.com/anotherhadi/spilltea"
 	"github.com/anotherhadi/spilltea/internal/config"
 	"github.com/anotherhadi/spilltea/internal/icons"
 	"github.com/anotherhadi/spilltea/internal/intercept"
 	"github.com/anotherhadi/spilltea/internal/keys"
-	spilltea "github.com/anotherhadi/spilltea"
 	"github.com/anotherhadi/spilltea/internal/style"
 	appUI "github.com/anotherhadi/spilltea/internal/ui/app"
 	homeUI "github.com/anotherhadi/spilltea/internal/ui/home"
@@ -27,6 +27,7 @@ func main() {
 		flagPluginsDir        = flag.String("plugins-dir", "", "path to plugins dir (overrides config)")
 		flagHost              = flag.String("host", "", "proxy host (overrides config)")
 		flagPort              = flag.IntP("port", "p", 0, "proxy port (overrides config)")
+		flagUpstreamProxy     = flag.String("upstream-proxy", "", "upstream proxy URL, e.g. http://user:pass@host:8888 (overrides config)")
 		flagVersion           = flag.BoolP("version", "v", false, "print version")
 		flagProject           = flag.StringP("project", "P", "", `project name to open directly, or "tmp" for a temporary session`)
 		flagAddDefaultPlugins = flag.Bool("add-default-plugins", false, "copy built-in example plugins into the plugins dir and exit")
@@ -85,6 +86,9 @@ func main() {
 	if *flagPort != 0 {
 		config.Global.App.Port = *flagPort
 	}
+	if *flagUpstreamProxy != "" {
+		config.Global.App.UpstreamProxy = *flagUpstreamProxy
+	}
 
 	addr := fmt.Sprintf("%s:%d", config.Global.App.Host, config.Global.App.Port)
 	// Check if the proxy port is available before starting the UI.
diff --git a/internal/config/config.go b/internal/config/config.go
index eb8af89..8dc2e32 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -18,11 +18,12 @@ type Config struct {
 	Version string `mapstructure:"-"`
 
 	App struct {
-		Host       string `mapstructure:"host"`
-		Port       int    `mapstructure:"port"`
-		CertDir    string `mapstructure:"cert_dir"`
-		ProjectDir string `mapstructure:"project_dir"`
-		PluginsDir string `mapstructure:"plugins_dir"`
+		Host          string `mapstructure:"host"`
+		Port          int    `mapstructure:"port"`
+		CertDir       string `mapstructure:"cert_dir"`
+		ProjectDir    string `mapstructure:"project_dir"`
+		PluginsDir    string `mapstructure:"plugins_dir"`
+		UpstreamProxy string `mapstructure:"upstream_proxy"`
 	} `mapstructure:"app"`
 
 	TUI struct {
diff --git a/internal/config/default_config.yaml b/internal/config/default_config.yaml
index 139a9bd..d428212 100644
--- a/internal/config/default_config.yaml
+++ b/internal/config/default_config.yaml
@@ -4,6 +4,7 @@ app:
   cert_dir: ~/.local/share/spilltea
   project_dir: ~/.local/share/spilltea
   plugins_dir: ~/.config/spilltea/plugins
+  upstream_proxy: "" # e.g. http://corporate-proxy:8888 or http://user:pass@host:8888
 
 intercept:
   default_intercept_enabled: true
diff --git a/internal/proxy/proxy.go b/internal/proxy/proxy.go
index 353ee52..a01860a 100644
--- a/internal/proxy/proxy.go
+++ b/internal/proxy/proxy.go
@@ -108,6 +108,7 @@ func Start(broker *intercept.Broker, mgr *plugins.Manager) error {
 		Addr:              addr,
 		StreamLargeBodies: 1024 * 1024 * 5,
 		CaRootPath:        caPath,
+		Upstream:          cfg.UpstreamProxy,
 	}
 
 	p, err := goproxy.NewProxy(opts)