diff --git a/src/cargo/ops/cargo_install.rs b/src/cargo/ops/cargo_install.rs
index 10dd8e091c6..8965b89480b 100644
--- a/src/cargo/ops/cargo_install.rs
+++ b/src/cargo/ops/cargo_install.rs
@@ -212,11 +212,19 @@ fn install_one(
                         src.path().display()
                     );
                 } else {
-                    bail!(
-                        "`{}` does not contain a Cargo.toml file. \
+                    if src.path().join("cargo.toml").exists() {
+                        bail!(
+                            "`{}` does not contain a Cargo.toml file, but found cargo.toml please try to rename it to Cargo.toml. \
                      --path must point to a directory containing a Cargo.toml file.",
-                        src.path().display()
-                    )
+                            src.path().display()
+                        )
+                    } else {
+                        bail!(
+                            "`{}` does not contain a Cargo.toml file. \
+                     --path must point to a directory containing a Cargo.toml file.",
+                            src.path().display()
+                        )
+                    }
                 }
             }
             select_pkg(
diff --git a/src/cargo/ops/cargo_read_manifest.rs b/src/cargo/ops/cargo_read_manifest.rs
index 732ef39d613..d55208b88f1 100644
--- a/src/cargo/ops/cargo_read_manifest.rs
+++ b/src/cargo/ops/cargo_read_manifest.rs
@@ -88,10 +88,19 @@ pub fn read_packages(
     if all_packages.is_empty() {
         match errors.pop() {
             Some(err) => Err(err),
-            None => Err(anyhow::format_err!(
-                "Could not find Cargo.toml in `{}`",
+            None => {
+                if find_project_manifest_exact(path, "cargo.toml").is_ok() {
+                    Err(anyhow::format_err!(
+                "Could not find Cargo.toml in `{}`, but found cargo.toml please try to rename it to Cargo.toml",
                 path.display()
-            )),
+            ))
+                } else {
+                    Err(anyhow::format_err!(
+                        "Could not find Cargo.toml in `{}`",
+                        path.display()
+                    ))
+                }
+            }
         }
     } else {
         Ok(all_packages.into_iter().map(|(_, v)| v).collect())
diff --git a/src/cargo/util/important_paths.rs b/src/cargo/util/important_paths.rs
index 4d34519c2ba..224c4ab8b86 100644
--- a/src/cargo/util/important_paths.rs
+++ b/src/cargo/util/important_paths.rs
@@ -4,19 +4,33 @@ use std::path::{Path, PathBuf};
 
 /// Finds the root `Cargo.toml`.
 pub fn find_root_manifest_for_wd(cwd: &Path) -> CargoResult<PathBuf> {
-    let file = "Cargo.toml";
+    let valid_cargo_toml_file_name = "Cargo.toml";
+    let invalid_cargo_toml_file_name = "cargo.toml";
+    let mut invalid_cargo_toml_path_exists = false;
+
     for current in paths::ancestors(cwd, None) {
-        let manifest = current.join(file);
+        let manifest = current.join(valid_cargo_toml_file_name);
         if manifest.exists() {
             return Ok(manifest);
         }
+        if current.join(invalid_cargo_toml_file_name).exists() {
+            invalid_cargo_toml_path_exists = true;
+        }
     }
 
-    anyhow::bail!(
-        "could not find `{}` in `{}` or any parent directory",
-        file,
+    if invalid_cargo_toml_path_exists {
+        anyhow::bail!(
+        "could not find `{}` in `{}` or any parent directory, but found cargo.toml please try to rename it to Cargo.toml",
+        valid_cargo_toml_file_name,
         cwd.display()
     )
+    } else {
+        anyhow::bail!(
+            "could not find `{}` in `{}` or any parent directory",
+            valid_cargo_toml_file_name,
+            cwd.display()
+        )
+    }
 }
 
 /// Returns the path to the `file` in `pwd`, if it exists.
diff --git a/tests/testsuite/build.rs b/tests/testsuite/build.rs
index fc11e666df0..0948ac1dad7 100644
--- a/tests/testsuite/build.rs
+++ b/tests/testsuite/build.rs
@@ -561,6 +561,24 @@ fn cargo_compile_without_manifest() {
         .run();
 }
 
+#[cargo_test]
+#[cfg(target_os = "linux")]
+fn cargo_compile_with_lowercase_cargo_toml() {
+    let p = project()
+        .no_manifest()
+        .file("cargo.toml", &basic_manifest("foo", "0.1.0"))
+        .file("src/lib.rs", &main_file(r#""i am foo""#, &[]))
+        .build();
+
+    p.cargo("build")
+        .with_status(101)
+        .with_stderr(
+            "[ERROR] could not find `Cargo.toml` in `[..]` or any parent directory, \
+        but found cargo.toml please try to rename it to Cargo.toml",
+        )
+        .run();
+}
+
 #[cargo_test]
 fn cargo_compile_with_invalid_code() {
     let p = project()
diff --git a/tests/testsuite/install.rs b/tests/testsuite/install.rs
index c2d3eef6fe4..dfb5f96f19a 100644
--- a/tests/testsuite/install.rs
+++ b/tests/testsuite/install.rs
@@ -399,6 +399,23 @@ fn install_target_dir() {
     assert!(path.exists());
 }
 
+#[cargo_test]
+#[cfg(target_os = "linux")]
+fn install_path_with_lowercase_cargo_toml() {
+    let toml = paths::root().join("cargo.toml");
+    fs::write(toml, "").unwrap();
+
+    cargo_process("install --path .")
+        .with_status(101)
+        .with_stderr(
+            "\
+[ERROR] `[CWD]` does not contain a Cargo.toml file, \
+but found cargo.toml please try to rename it to Cargo.toml. --path must point to a directory containing a Cargo.toml file.
+",
+        )
+        .run();
+}
+
 #[cargo_test]
 fn multiple_crates_error() {
     let p = git::repo(&paths::root().join("foo"))
@@ -760,6 +777,26 @@ fn git_repo() {
     assert_has_installed_exe(cargo_home(), "foo");
 }
 
+#[cargo_test]
+#[cfg(target_os = "linux")]
+fn git_repo_with_lowercase_cargo_toml() {
+    let p = git::repo(&paths::root().join("foo"))
+        .file("cargo.toml", &basic_manifest("foo", "0.1.0"))
+        .file("src/main.rs", "fn main() {}")
+        .build();
+
+    cargo_process("install --git")
+        .arg(p.url().to_string())
+        .with_status(101)
+        .with_stderr(
+            "\
+[UPDATING] git repository [..]
+[ERROR] Could not find Cargo.toml in `[..]`, but found cargo.toml please try to rename it to Cargo.toml
+",
+        )
+        .run();
+}
+
 #[cargo_test]
 fn list() {
     pkg("foo", "0.0.1");