diff --git a/CHANGELOG.next.toml b/CHANGELOG.next.toml
index d546c0b6f0..8ef2fea4c5 100644
--- a/CHANGELOG.next.toml
+++ b/CHANGELOG.next.toml
@@ -86,3 +86,9 @@ message = "Fix bug in `CredentialsProcess` provider where `expiry` was incorrect
 references = ["smithy-rs#3335", "aws-sdk-rust#1021"]
 meta = { "breaking" = false, "tada" = false, "bug" = true }
 author = "rcoh"
+
+[[aws-sdk-rust]]
+message = "~/.aws/config and ~/.aws/credentials now parse keys in a case-insensitive way. This means the `AWS_SECRET_ACCESS_KEY` is supported in addition to `aws_secret_access_key`."
+references = ["aws-sdk#574", "aws-sdk-rust#1020", "smithy-rs#3344"]
+meta = { "breaking" = false, "bug" = true, "tada" = false }
+author = "rcoh"
diff --git a/aws/rust-runtime/aws-config/src/default_provider/credentials.rs b/aws/rust-runtime/aws-config/src/default_provider/credentials.rs
index f64986be7c..2999117c29 100644
--- a/aws/rust-runtime/aws-config/src/default_provider/credentials.rs
+++ b/aws/rust-runtime/aws-config/src/default_provider/credentials.rs
@@ -268,6 +268,7 @@ mod test {
 
     make_test!(prefer_environment);
     make_test!(profile_static_keys);
+    make_test!(profile_static_keys_case_insensitive);
     make_test!(web_identity_token_env);
     make_test!(web_identity_source_profile_no_env);
     make_test!(web_identity_token_invalid_jwt);
diff --git a/aws/rust-runtime/aws-config/src/profile/parser.rs b/aws/rust-runtime/aws-config/src/profile/parser.rs
index 6a83e908af..dfa705823e 100644
--- a/aws/rust-runtime/aws-config/src/profile/parser.rs
+++ b/aws/rust-runtime/aws-config/src/profile/parser.rs
@@ -3,7 +3,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-use crate::profile::parser::parse::parse_profile_file;
+use crate::profile::parser::parse::{parse_profile_file, to_ascii_lowercase};
 use crate::profile::parser::source::Source;
 use crate::profile::profile_file::ProfileFiles;
 use aws_types::os_shim_internal::{Env, Fs};
@@ -169,7 +169,9 @@ impl Profile {
 
     /// Returns a reference to the property named `name`
     pub fn get(&self, name: &str) -> Option<&str> {
-        self.properties.get(name).map(|prop| prop.value())
+        self.properties
+            .get(to_ascii_lowercase(name).as_ref())
+            .map(|prop| prop.value())
     }
 }
 
diff --git a/aws/rust-runtime/aws-config/src/profile/parser/normalize.rs b/aws/rust-runtime/aws-config/src/profile/parser/normalize.rs
index 5b3b5c1ea8..36518d9ef7 100644
--- a/aws/rust-runtime/aws-config/src/profile/parser/normalize.rs
+++ b/aws/rust-runtime/aws-config/src/profile/parser/normalize.rs
@@ -113,9 +113,9 @@ pub(super) fn merge_in(
     }
 }
 
-fn merge_into_base(target: &mut Profile, profile: HashMap<&str, Cow<'_, str>>) {
+fn merge_into_base(target: &mut Profile, profile: HashMap<Cow<'_, str>, Cow<'_, str>>) {
     for (k, v) in profile {
-        match validate_identifier(k) {
+        match validate_identifier(k.as_ref()) {
             Ok(k) => {
                 target
                     .properties
@@ -146,6 +146,7 @@ fn validate_identifier(input: &str) -> Result<&str, ()> {
 
 #[cfg(test)]
 mod tests {
+    use std::borrow::Cow;
     use std::collections::HashMap;
 
     use tracing_test::traced_test;
@@ -218,7 +219,7 @@ mod tests {
         let mut profile: RawProfileSet<'_> = HashMap::new();
         profile.insert("default", {
             let mut out = HashMap::new();
-            out.insert("invalid key", "value".into());
+            out.insert(Cow::Borrowed("invalid key"), "value".into());
             out
         });
         let mut base = ProfileSet::empty();
diff --git a/aws/rust-runtime/aws-config/src/profile/parser/parse.rs b/aws/rust-runtime/aws-config/src/profile/parser/parse.rs
index 1d3c3acb05..062c32fa34 100644
--- a/aws/rust-runtime/aws-config/src/profile/parser/parse.rs
+++ b/aws/rust-runtime/aws-config/src/profile/parser/parse.rs
@@ -19,7 +19,7 @@ use std::error::Error;
 use std::fmt::{self, Display, Formatter};
 
 /// A set of profiles that still carries a reference to the underlying data
-pub(super) type RawProfileSet<'a> = HashMap<&'a str, HashMap<&'a str, Cow<'a, str>>>;
+pub(super) type RawProfileSet<'a> = HashMap<&'a str, HashMap<Cow<'a, str>, Cow<'a, str>>>;
 
 /// Characters considered to be whitespace by the spec
 ///
@@ -98,7 +98,7 @@ enum State<'a> {
     Starting,
     ReadingProfile {
         profile: &'a str,
-        property: Option<&'a str>,
+        property: Option<Cow<'a, str>>,
         is_subproperty: bool,
     },
 }
@@ -152,7 +152,7 @@ impl<'a> Parser<'a> {
             .map_err(|err| err.into_error("property", location.clone()))?;
         self.state = State::ReadingProfile {
             profile: name,
-            property: Some(k),
+            property: Some(k.clone()),
             is_subproperty: v.is_empty(),
         };
         current_profile.insert(k, v.into());
@@ -184,7 +184,7 @@ impl<'a> Parser<'a> {
                 self.data
                     .get_mut(*profile)
                     .expect("profile must exist")
-                    .get_mut(*property)
+                    .get_mut(property.as_ref())
                     .expect("property must exist")
             }
             State::ReadingProfile {
@@ -246,7 +246,7 @@ impl PropertyError {
 }
 
 /// Parse a property line into a key-value pair
-fn parse_property_line(line: &str) -> Result<(&str, &str), PropertyError> {
+fn parse_property_line(line: &str) -> Result<(Cow<'_, str>, &str), PropertyError> {
     let line = prepare_line(line, true);
     let (k, v) = line.split_once('=').ok_or(PropertyError::NoEquals)?;
     let k = k.trim_matches(WHITESPACE);
@@ -254,7 +254,15 @@ fn parse_property_line(line: &str) -> Result<(&str, &str), PropertyError> {
     if k.is_empty() {
         return Err(PropertyError::NoName);
     }
-    Ok((k, v))
+    Ok((to_ascii_lowercase(k), v))
+}
+
+pub(crate) fn to_ascii_lowercase(s: &str) -> Cow<'_, str> {
+    if s.bytes().any(|b| b.is_ascii_uppercase()) {
+        Cow::Owned(s.to_ascii_lowercase())
+    } else {
+        Cow::Borrowed(s)
+    }
 }
 
 /// Prepare a line for parsing
@@ -291,23 +299,30 @@ mod test {
     use crate::profile::parser::parse::{parse_property_line, PropertyError};
     use crate::profile::parser::source::File;
     use crate::profile::profile_file::ProfileFileKind;
+    use std::borrow::Cow;
 
     // most test cases covered by the JSON test suite
 
     #[test]
     fn property_parsing() {
-        assert_eq!(parse_property_line("a = b"), Ok(("a", "b")));
-        assert_eq!(parse_property_line("a=b"), Ok(("a", "b")));
-        assert_eq!(parse_property_line("a = b "), Ok(("a", "b")));
-        assert_eq!(parse_property_line(" a = b "), Ok(("a", "b")));
-        assert_eq!(parse_property_line(" a = b 🐱 "), Ok(("a", "b 🐱")));
+        fn ok<'a>(key: &'a str, value: &'a str) -> Result<(Cow<'a, str>, &'a str), PropertyError> {
+            Ok((Cow::Borrowed(key), value))
+        }
+
+        assert_eq!(parse_property_line("a = b"), ok("a", "b"));
+        assert_eq!(parse_property_line("a=b"), ok("a", "b"));
+        assert_eq!(parse_property_line("a = b "), ok("a", "b"));
+        assert_eq!(parse_property_line(" a = b "), ok("a", "b"));
+        assert_eq!(parse_property_line(" a = b 🐱 "), ok("a", "b 🐱"));
         assert_eq!(parse_property_line("a b"), Err(PropertyError::NoEquals));
         assert_eq!(parse_property_line("= b"), Err(PropertyError::NoName));
-        assert_eq!(parse_property_line("a =    "), Ok(("a", "")));
+        assert_eq!(parse_property_line("a =    "), ok("a", ""));
         assert_eq!(
             parse_property_line("something_base64=aGVsbG8gZW50aHVzaWFzdGljIHJlYWRlcg=="),
-            Ok(("something_base64", "aGVsbG8gZW50aHVzaWFzdGljIHJlYWRlcg=="))
+            ok("something_base64", "aGVsbG8gZW50aHVzaWFzdGljIHJlYWRlcg==")
         );
+
+        assert_eq!(parse_property_line("ABc = DEF"), ok("abc", "DEF"));
     }
 
     #[test]
diff --git a/aws/rust-runtime/aws-config/test-data/default-provider-chain/profile_static_keys_case_insensitive/env.json b/aws/rust-runtime/aws-config/test-data/default-provider-chain/profile_static_keys_case_insensitive/env.json
new file mode 100644
index 0000000000..55fcfbeb05
--- /dev/null
+++ b/aws/rust-runtime/aws-config/test-data/default-provider-chain/profile_static_keys_case_insensitive/env.json
@@ -0,0 +1,3 @@
+{
+  "HOME": "/home"
+}
diff --git a/aws/rust-runtime/aws-config/test-data/default-provider-chain/profile_static_keys_case_insensitive/fs/home/.aws/config b/aws/rust-runtime/aws-config/test-data/default-provider-chain/profile_static_keys_case_insensitive/fs/home/.aws/config
new file mode 100644
index 0000000000..a8c11c6e8c
--- /dev/null
+++ b/aws/rust-runtime/aws-config/test-data/default-provider-chain/profile_static_keys_case_insensitive/fs/home/.aws/config
@@ -0,0 +1,2 @@
+[default]
+region = us-east-1
diff --git a/aws/rust-runtime/aws-config/test-data/default-provider-chain/profile_static_keys_case_insensitive/fs/home/.aws/credentials b/aws/rust-runtime/aws-config/test-data/default-provider-chain/profile_static_keys_case_insensitive/fs/home/.aws/credentials
new file mode 100644
index 0000000000..bac520774d
--- /dev/null
+++ b/aws/rust-runtime/aws-config/test-data/default-provider-chain/profile_static_keys_case_insensitive/fs/home/.aws/credentials
@@ -0,0 +1,3 @@
+[default]
+AWS_ACCESS_KEY_ID = correct_key
+AWS_SECRET_ACCESS_KEY = correct_secret
diff --git a/aws/rust-runtime/aws-config/test-data/default-provider-chain/profile_static_keys_case_insensitive/http-traffic.json b/aws/rust-runtime/aws-config/test-data/default-provider-chain/profile_static_keys_case_insensitive/http-traffic.json
new file mode 100644
index 0000000000..489a35c611
--- /dev/null
+++ b/aws/rust-runtime/aws-config/test-data/default-provider-chain/profile_static_keys_case_insensitive/http-traffic.json
@@ -0,0 +1,5 @@
+{
+  "events": [],
+  "docs": "test case uses static creds, no network requests",
+  "version": "V0"
+}
diff --git a/aws/rust-runtime/aws-config/test-data/default-provider-chain/profile_static_keys_case_insensitive/test-case.json b/aws/rust-runtime/aws-config/test-data/default-provider-chain/profile_static_keys_case_insensitive/test-case.json
new file mode 100644
index 0000000000..c56a02bac6
--- /dev/null
+++ b/aws/rust-runtime/aws-config/test-data/default-provider-chain/profile_static_keys_case_insensitive/test-case.json
@@ -0,0 +1,10 @@
+{
+  "name": "profile_static_keys",
+  "docs": "load static keys from a profile",
+  "result": {
+    "Ok": {
+      "access_key_id": "correct_key",
+      "secret_access_key": "correct_secret"
+    }
+  }
+}
diff --git a/aws/rust-runtime/aws-config/test-data/profile-parser-tests.json b/aws/rust-runtime/aws-config/test-data/profile-parser-tests.json
index 70ce8a046e..6f6f2a8a70 100644
--- a/aws/rust-runtime/aws-config/test-data/profile-parser-tests.json
+++ b/aws/rust-runtime/aws-config/test-data/profile-parser-tests.json
@@ -452,6 +452,19 @@
         }
       }
     },
+    {
+      "name": "Duplicate properties in duplicate profiles use the last one defined (case insensitive).",
+      "input": {
+        "configFile": "[profile foo]\nName = value\n[profile foo]\nname = value2"
+      },
+      "output": {
+        "profiles": {
+          "foo": {
+            "name": "value2"
+          }
+        }
+      }
+    },
     {
       "name": "Default profile with profile prefix overrides default profile without prefix when profile prefix is first.",
       "input": {
@@ -518,7 +531,7 @@
       "output": {
         "profiles": {
           "foo": {
-            "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_": "value"
+            "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz0123456789-_": "value"
           }
         }
       }
diff --git a/tools/ci-build/smithy-rs-tool-common/src/changelog.rs b/tools/ci-build/smithy-rs-tool-common/src/changelog.rs
index 6cc10e5258..f68325d463 100644
--- a/tools/ci-build/smithy-rs-tool-common/src/changelog.rs
+++ b/tools/ci-build/smithy-rs-tool-common/src/changelog.rs
@@ -108,7 +108,7 @@ impl FromStr for Reference {
             ),
             Some((repo, number)) => {
                 let number = number.parse::<usize>()?;
-                if !matches!(repo, "smithy-rs" | "aws-sdk-rust") {
+                if !matches!(repo, "smithy-rs" | "aws-sdk-rust" | "aws-sdk") {
                     bail!("unexpected repo: {}", repo);
                 }
                 Ok(Reference {