diff --git a/codeflash/cli_cmds/cli.py b/codeflash/cli_cmds/cli.py
index d76e60a11..2a445cc7f 100644
--- a/codeflash/cli_cmds/cli.py
+++ b/codeflash/cli_cmds/cli.py
@@ -478,5 +478,12 @@ def _build_parser() -> ArgumentParser:
         action="store_true",
         help="Subagent mode: skip all interactive prompts with sensible defaults. Designed for AI agent integrations.",
     )
+    parser.add_argument(
+        "--since-commit",
+        type=str,
+        default=None,
+        help="Optimize functions changed since this commit hash (diff from this commit to HEAD). "
+        "Useful when multiple commits were made in a session.",
+    )
 
     return parser
diff --git a/codeflash/code_utils/git_utils.py b/codeflash/code_utils/git_utils.py
index 21afc3bd7..7cb31416c 100644
--- a/codeflash/code_utils/git_utils.py
+++ b/codeflash/code_utils/git_utils.py
@@ -19,7 +19,11 @@
 
 
 def get_git_diff(
-    repo_directory: Path | None = None, *, only_this_commit: Optional[str] = None, uncommitted_changes: bool = False
+    repo_directory: Path | None = None,
+    *,
+    only_this_commit: Optional[str] = None,
+    uncommitted_changes: bool = False,
+    since_commit: Optional[str] = None,
 ) -> dict[str, list[int]]:
     from codeflash.languages.registry import get_supported_extensions
 
@@ -30,7 +34,12 @@ def get_git_diff(
     # Use all registered extensions (Python + JS/TS + Java etc.) rather than
     # current_language_support() which defaults to Python before language detection runs.
     supported_extensions = set(get_supported_extensions())
-    if only_this_commit:
+    if since_commit:
+        # Diff from a base commit to HEAD — captures all changes across multiple commits
+        uni_diff_text = repository.git.diff(
+            since_commit, commit.hexsha, ignore_blank_lines=True, ignore_space_at_eol=True
+        )
+    elif only_this_commit:
         uni_diff_text = repository.git.diff(
             only_this_commit + "^1", only_this_commit, ignore_blank_lines=True, ignore_space_at_eol=True
         )
diff --git a/codeflash/discovery/functions_to_optimize.py b/codeflash/discovery/functions_to_optimize.py
index 9c8776f75..3a8b86e9f 100644
--- a/codeflash/discovery/functions_to_optimize.py
+++ b/codeflash/discovery/functions_to_optimize.py
@@ -213,6 +213,7 @@ def get_functions_to_optimize(
     project_root: Path,
     module_root: Path,
     previous_checkpoint_functions: dict[str, dict[str, str]] | None = None,
+    since_commit: str | None = None,
 ) -> tuple[dict[Path, list[FunctionToOptimize]], int, Path | None]:
     assert sum([bool(optimize_all), bool(replay_test), bool(file)]) <= 1, (
         "Only one of optimize_all, replay_test, or file should be provided"
@@ -313,10 +314,13 @@ def get_functions_to_optimize(
 
                 functions[file] = [found_function]
         else:
-            logger.info("Finding all functions modified in the current git diff ...")
+            if since_commit:
+                logger.info("Finding all functions modified since commit %s ...", since_commit[:8])
+            else:
+                logger.info("Finding all functions modified in the current git diff ...")
             console.rule()
             ph("cli-optimizing-git-diff")
-            functions = get_functions_within_git_diff(uncommitted_changes=False)
+            functions = get_functions_within_git_diff(uncommitted_changes=False, since_commit=since_commit)
         filtered_modified_functions, functions_count = filter_functions(
             functions, test_cfg.tests_root, ignore_paths, project_root, module_root, previous_checkpoint_functions
         )
@@ -325,8 +329,12 @@ def get_functions_to_optimize(
         return filtered_modified_functions, functions_count, trace_file_path
 
 
-def get_functions_within_git_diff(uncommitted_changes: bool) -> dict[Path, list[FunctionToOptimize]]:
-    modified_lines: dict[str, list[int]] = get_git_diff(uncommitted_changes=uncommitted_changes)
+def get_functions_within_git_diff(
+    uncommitted_changes: bool, since_commit: str | None = None
+) -> dict[Path, list[FunctionToOptimize]]:
+    modified_lines: dict[str, list[int]] = get_git_diff(
+        uncommitted_changes=uncommitted_changes, since_commit=since_commit
+    )
     return get_functions_within_lines(modified_lines)
 
 
diff --git a/codeflash/optimization/optimizer.py b/codeflash/optimization/optimizer.py
index 49eaa23e5..7e4586670 100644
--- a/codeflash/optimization/optimizer.py
+++ b/codeflash/optimization/optimizer.py
@@ -158,6 +158,7 @@ def get_optimizable_functions(self) -> tuple[dict[Path, list[FunctionToOptimize]
             project_root=project_root,
             module_root=module_root,
             previous_checkpoint_functions=self.args.previous_checkpoint_functions,
+            since_commit=getattr(self.args, "since_commit", None),
         )
 
         # Remap discovered file paths from the original repo to the worktree so