diff --git a/compiler-cli/src/publish.rs b/compiler-cli/src/publish.rs
index 159454d47fc..6bba30955f5 100644
--- a/compiler-cli/src/publish.rs
+++ b/compiler-cli/src/publish.rs
@@ -4,7 +4,7 @@ use flate2::{Compression, write::GzEncoder};
 use gleam_core::{
     Error, Result,
     analyse::TargetSupport,
-    build::{Codegen, Compile, Mode, Options, Package, Target},
+    build::{Codegen, Compile, Mode, Options, Origin, Package, Target},
     config::{GleamVersion, PackageConfig, SpdxLicense},
     docs::DocContext,
     error::{SmallVersion, wrap},
@@ -338,8 +338,21 @@ fn do_build_hex_tarball(paths: &ProjectPaths, config: &mut PackageConfig) -> Res
     // refuse to publish as the package is not yet finished.
     let mut modules_containing_todo = vec![];
     let mut modules_containing_echo = vec![];
+    let dev_dependencies: Vec<&EcoString> = config.dev_dependencies.keys().collect();
 
     for module in built.root_package.modules.iter() {
+        for (imported_module, _) in &module.dependencies {
+            if let Some(import_info) = built.module_interfaces.get(imported_module) {
+                let package = &import_info.package;
+                if dev_dependencies.contains(&package) && module.origin == Origin::Src {
+                    return Err(Error::CannotPublishLeakedDevDependency {
+                        module: module.name.clone(),
+                        package: package.clone(),
+                    });
+                }
+            }
+        }
+
         if module.ast.type_info.contains_todo() {
             modules_containing_todo.push(module.name.clone());
         } else if module.ast.type_info.contains_echo {
diff --git a/compiler-core/src/error.rs b/compiler-core/src/error.rs
index fd0d67019af..b08e2a69356 100644
--- a/compiler-core/src/error.rs
+++ b/compiler-core/src/error.rs
@@ -298,6 +298,12 @@ file_names.iter().map(|x| x.as_str()).join(", "))]
     )]
     CannotPublishLeakedInternalType { unfinished: Vec<EcoString> },
 
+    #[error("The module imports a dev dependency")]
+    CannotPublishLeakedDevDependency {
+        module: EcoString,
+        package: EcoString,
+    },
+
     #[error("Publishing packages to reserve names is not permitted")]
     HexPackageSquatting,
 
@@ -1083,6 +1089,17 @@ Please make sure internal types do not appear in public functions and try again.
                 location: None,
             }],
 
+            Error::CannotPublishLeakedDevDependency { module, package } => {
+                let text = &format!("The module `{module}` is being imported from `{package}`, but package is not a direct dependency of your project.\nRun this command to add it to your dependencies:\n\tgleam add {package}");
+                vec![Diagnostic {
+                    title: "Development dependency imported".into(),
+                    text: text.to_string(),
+                    hint: None,
+                    level: Level::Error,
+                    location: None
+                }]
+            }
+
             Error::UnableToFindProjectRoot { path } => {
                 let text = wrap_format!(
                     "We were unable to find gleam.toml.