diff --git a/src/rapids_dependency_file_generator/_rapids_dependency_file_generator.py b/src/rapids_dependency_file_generator/_rapids_dependency_file_generator.py
index 4fc186c..b201e36 100644
--- a/src/rapids_dependency_file_generator/_rapids_dependency_file_generator.py
+++ b/src/rapids_dependency_file_generator/_rapids_dependency_file_generator.py
@@ -389,7 +389,20 @@ def make_dependency_files(
                         if file_type not in specific_entry.output_types:
                             continue
 
-                        found = False
+                        # Ensure that all specific matrices are unique
+                        num_matrices = len(specific_entry.matrices)
+                        num_unique = len(
+                            {
+                                frozenset(specific_matrices_entry.matrix.items())
+                                for specific_matrices_entry in specific_entry.matrices
+                            }
+                        )
+                        if num_matrices != num_unique:
+                            err = f"All matrix entries must be unique. Found duplicates in '{include}':"
+                            for specific_matrices_entry in specific_entry.matrices:
+                                err += f"\n - {specific_matrices_entry.matrix}"
+                            raise ValueError(err)
+
                         fallback_entry = None
                         for specific_matrices_entry in specific_entry.matrices:
                             # An empty `specific_matrices_entry["matrix"]` is
@@ -403,18 +416,12 @@ def make_dependency_files(
                                 continue
 
                             if should_use_specific_entry(matrix_combo, specific_matrices_entry.matrix):
-                                # Raise an error if multiple specific entries
-                                # (not including the fallback_entry) match a
-                                # requested matrix combination.
-                                if found:
-                                    raise ValueError(f"Found multiple matches for matrix {matrix_combo}")
-                                found = True
                                 # A package list may be empty as a way to
                                 # indicate that for some matrix elements no
                                 # packages should be installed.
                                 dependencies.extend(specific_matrices_entry.packages or [])
-
-                        if not found:
+                                break
+                        else:
                             if fallback_entry:
                                 dependencies.extend(fallback_entry.packages)
                             else:
diff --git a/tests/examples/duplicate-specific-matrix-entries/dependencies.yaml b/tests/examples/duplicate-specific-matrix-entries/dependencies.yaml
new file mode 100644
index 0000000..54a262f
--- /dev/null
+++ b/tests/examples/duplicate-specific-matrix-entries/dependencies.yaml
@@ -0,0 +1,24 @@
+files:
+  all:
+    output: conda
+    conda_dir: output/actual
+    matrix:
+      cuda: ["11.5", "11.8"]
+    includes:
+      - cudatoolkit
+channels:
+  - rapidsai
+  - conda-forge
+dependencies:
+  cudatoolkit:
+    specific:
+      - output_types: conda
+        matrices:
+          - matrix:
+              cuda: "11.5"
+            packages:
+              - cudatoolkit=11.5
+          - matrix:
+              cuda: "11.5"
+            packages:
+              - cudatoolkit=11.5
diff --git a/tests/examples/specific-fallback-multiple-matches/dependencies.yaml b/tests/examples/specific-fallback-multiple-matches/dependencies.yaml
new file mode 100644
index 0000000..0d33b4f
--- /dev/null
+++ b/tests/examples/specific-fallback-multiple-matches/dependencies.yaml
@@ -0,0 +1,27 @@
+files:
+  all:
+    output: conda
+    conda_dir: output/actual
+    matrix:
+      cuda: ["11.5", "11.8"]
+    includes:
+      - cudatoolkit
+channels:
+  - rapidsai
+  - conda-forge
+dependencies:
+  cudatoolkit:
+    specific:
+      - output_types: conda
+        matrices:
+          - matrix:
+              cuda: "11.5"
+            packages:
+              - cudatoolkit=11.5
+          - matrix:
+              cuda: "11.*"
+            packages:
+              - cudatoolkit=11.*
+          - matrix:
+            packages:
+              - cudatoolkit
diff --git a/tests/examples/specific-fallback-multiple-matches/output/expected/all_cuda-115.yaml b/tests/examples/specific-fallback-multiple-matches/output/expected/all_cuda-115.yaml
new file mode 100644
index 0000000..f9ab85d
--- /dev/null
+++ b/tests/examples/specific-fallback-multiple-matches/output/expected/all_cuda-115.yaml
@@ -0,0 +1,8 @@
+# This file is generated by `rapids-dependency-file-generator`.
+# To make changes, edit ../../dependencies.yaml and run `rapids-dependency-file-generator`.
+channels:
+- rapidsai
+- conda-forge
+dependencies:
+- cudatoolkit=11.5
+name: all_cuda-115
diff --git a/tests/examples/specific-fallback-multiple-matches/output/expected/all_cuda-118.yaml b/tests/examples/specific-fallback-multiple-matches/output/expected/all_cuda-118.yaml
new file mode 100644
index 0000000..f9f9290
--- /dev/null
+++ b/tests/examples/specific-fallback-multiple-matches/output/expected/all_cuda-118.yaml
@@ -0,0 +1,8 @@
+# This file is generated by `rapids-dependency-file-generator`.
+# To make changes, edit ../../dependencies.yaml and run `rapids-dependency-file-generator`.
+channels:
+- rapidsai
+- conda-forge
+dependencies:
+- cudatoolkit=11.*
+name: all_cuda-118
diff --git a/tests/test_examples.py b/tests/test_examples.py
index c47ca35..2c5294d 100644
--- a/tests/test_examples.py
+++ b/tests/test_examples.py
@@ -14,11 +14,12 @@
 
 # Erroneous examples raise runtime errors from the generator.
 _erroneous_examples = [
+    "duplicate-specific-matrix-entries",
     "no-specific-match",
-    "pyproject_matrix_multi",
-    "pyproject_bad_key",
     "pyproject-no-extras",
-    "requirements-pip-dict"
+    "pyproject_bad_key",
+    "pyproject_matrix_multi",
+    "requirements-pip-dict",
 ]
 EXAMPLE_FILES = [
     pth