diff --git a/CHANGES.txt b/CHANGES.txt
index d96714030..0229fb906 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -19,6 +19,9 @@ RELEASE  VERSION/DATE TO BE FILLED IN LATER
   From William Deegan:
         - Fix SCons Docbook schema to work with lxml > 5
 
+  From Keith F Prussing:
+    -  Fix multiple extension stripping for BibTeX and Biber processing
+
 
 RELEASE 4.10.1 - Sun, 16 Nov 2025 10:51:57 -0700
 
diff --git a/RELEASE.txt b/RELEASE.txt
index 8141c8c57..bdee35879 100644
--- a/RELEASE.txt
+++ b/RELEASE.txt
@@ -33,6 +33,7 @@ FIXES
 -----
 
 - List fixes of outright bugs
+- Fix multiple extension stripping for BibTeX and Biber processing
 
 IMPROVEMENTS
 ------------
diff --git a/SCons/Tool/tex.py b/SCons/Tool/tex.py
index 6d366334a..952c8f6fc 100644
--- a/SCons/Tool/tex.py
+++ b/SCons/Tool/tex.py
@@ -340,8 +340,9 @@ def check_content_hash(filenode, suffix) -> bool:
                     if 'bibdata' in content:
                         if Verbose:
                             print("Need to run bibtex on ",auxfilename)
-                        bibfile = env.fs.File(SCons.Util.splitext(target_aux)[0])
-                        result = BibTeXAction(bibfile, bibfile, env)
+                        auxfile = env.fs.File(target_aux)
+                        bibfile = env.fs.File(SCons.Util.splitext(target_aux)[0] + ".bib")
+                        result = BibTeXAction(bibfile, auxfile, env)
                         if result != 0:
                             check_file_error_message(env['BIBTEX'], 'blg')
                         check_content_hash(suffix_nodes[".bbl"], ".bbl")
@@ -364,8 +365,9 @@ def check_content_hash(filenode, suffix) -> bool:
                     if 'bibdata' in content:
                         if Verbose:
                             print("Need to run biber on ",bcffilename)
-                        bibfile = env.fs.File(SCons.Util.splitext(target_bcf)[0])
-                        result = BiberAction(bibfile, bibfile, env)
+                        auxfile = env.fs.File(target_aux)
+                        bibfile = env.fs.File(SCons.Util.splitext(target_aux)[0] + ".bbl")
+                        result = BiberAction(bibfile, auxfile, env)
                         if result != 0:
                             check_file_error_message(env['BIBER'], 'blg')
                         check_content_hash(suffix_nodes[".bbl"], ".bbl")
diff --git a/test/TEX/bibtex-extra-extension.py b/test/TEX/bibtex-extra-extension.py
new file mode 100644
index 000000000..d2b1231b2
--- /dev/null
+++ b/test/TEX/bibtex-extra-extension.py
@@ -0,0 +1,80 @@
+#!/usr/bin/env python
+#
+# MIT License
+#
+# Copyright The SCons Foundation
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be included
+# in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+"""
+Verify that running LaTeX with a file named main.extra.tex pulls the
+right bibliography file.
+"""
+
+import TestSCons
+
+test = TestSCons.TestSCons()
+
+pdflatex = test.where_is('pdflatex')
+
+if not pdflatex:
+    test.skip_test("Could not find 'pdflatex'; skipping test(s).\n")
+
+mains = ["main.tex", "main.extra.tex"]
+
+test.write(["SConstruct"], f"""\
+import os
+env = Environment(tools=['pdftex', 'tex'])
+env.PDF({mains})
+""")
+
+body_content = r"""\documentclass{article}
+\begin{document}
+SCons \cite{scons}!
+\bibliography{references}
+\bibliographystyle{plain}
+\end{document}
+"""
+
+for _ in mains:
+    test.write(_, body_content)
+
+test.write("references.bib", r"""
+@misc{scons,
+    title = {SCons},
+    url = {https://scons.org},
+    language = {en-US},
+    urldate = {2025-08-15},
+    author = {{SCons} {Foundation}},
+    year = {2025},
+}
+""")
+
+test.run()
+
+pdfs = [test.normalize_pdf(test.read(_[:-3] + "pdf")) for _ in mains]
+test.fail_test(pdfs[0] != pdfs[1])
+test.pass_test()
+
+# Local Variables:
+# tab-width:4
+# indent-tabs-mode:nil
+# End:
+# vim: set expandtab tabstop=4 shiftwidth=4: