diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e8d9483342..ebe1210567 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -363,7 +363,7 @@ jobs:
                             CLANG_FORMAT_EXE=clang-format-22
                             EXTRA_DEP_PACKAGES="clang-format-22"
 
-          - desc: latest releases gcc15 C++23 py3.12 avx2 exr3.4 ocio2.4
+          - desc: latest releases gcc15 C++23 py3.12 avx2 exr3.5 ocio2.4
             nametag: linux-latest-releases
             runner: ubuntu-24.04
             # cc_compiler: gcc-13
@@ -372,7 +372,7 @@ jobs:
             fmt_ver: 12.2.0
             fmt_commit: 1be298e1bd68957e4cd352e1f676f00e07dcfb57
             opencolorio_ver: v2.5.2
-            openexr_ver: v3.4.15
+            openexr_ver: v3.5.0
             pybind11_ver: v3.1.0
             python_ver: "3.12"
             oiio_python_bindings_backend: both
@@ -406,7 +406,8 @@ jobs:
             cxx_std: 26
             fmt_ver: main
             opencolorio_ver: main
-            openexr_ver: main
+            openexr_ver: v3.5.1
+            # TODO: bump openexr_ver back to "main" after lj2k bug is fixed
             pybind11_ver: master
             python_ver: "3.12"
             oiio_python_bindings_backend: both
@@ -470,7 +471,7 @@ jobs:
             setenvs: export USE_OPENVDB=0
                             openjph_CMAKE_C_COMPILER=gcc
                             openjph_CMAKE_CXX_COMPILER=g++
-          - desc: Linux ARM latest releases gcc14 C++20 py3.12 exr3.4 ocio2.4
+          - desc: Linux ARM latest releases gcc14 C++20 py3.12 exr3.5 ocio2.4
             nametag: linux-arm-latest-releases
             runner: ubuntu-24.04-arm
             cc_compiler: gcc-14
@@ -479,7 +480,7 @@ jobs:
             fmt_ver: 12.2.0
             fmt_commit: 1be298e1bd68957e4cd352e1f676f00e07dcfb57
             opencolorio_ver: v2.5.2
-            openexr_ver: v3.4.15
+            openexr_ver: v3.5.0
             pybind11_ver: v3.1.0
             python_ver: "3.12"
             oiio_python_bindings_backend: both
@@ -495,7 +496,7 @@ jobs:
                             USE_OPENVDB=0
                             nanobind_GIT_TAG=v3.0.0
                             nanobind_GIT_COMMIT=1bd3139721d6176dfb10979b7219ccb58ef8aafa
-          - desc: Linux ARM latest releases clang18 C++20 py3.12 exr3.4 ocio2.4
+          - desc: Linux ARM latest releases clang18 C++20 py3.12 exr3.5 ocio2.4
             nametag: linux-arm-latest-releases-clang
             runner: ubuntu-24.04-arm
             cc_compiler: clang-18
@@ -504,7 +505,7 @@ jobs:
             fmt_ver: 12.2.0
             fmt_commit: 1be298e1bd68957e4cd352e1f676f00e07dcfb57
             opencolorio_ver: v2.5.2
-            openexr_ver: v3.4.15
+            openexr_ver: v3.5.0
             pybind11_ver: v3.1.0
             python_ver: "3.12"
             oiio_python_bindings_backend: both
diff --git a/src/build-scripts/build_openexr.bash b/src/build-scripts/build_openexr.bash
index 43e5fb1aa3..e0c76cceab 100755
--- a/src/build-scripts/build_openexr.bash
+++ b/src/build-scripts/build_openexr.bash
@@ -11,7 +11,7 @@ set -ex
 
 # Which OpenEXR to retrieve, how to build it
 OPENEXR_REPO=${OPENEXR_REPO:=https://github.com/AcademySoftwareFoundation/openexr.git}
-OPENEXR_VERSION=${OPENEXR_VERSION:=v3.4.15}
+OPENEXR_VERSION=${OPENEXR_VERSION:=v3.5.0}
 
 # Where to install the final results
 LOCAL_DEPS_DIR=${LOCAL_DEPS_DIR:=${PWD}/ext}
@@ -64,4 +64,3 @@ export OpenEXR_ROOT=$OPENEXR_INSTALL_DIR
 export OPENEXR_ROOT=$OPENEXR_INSTALL_DIR
 export OPENEXR_LIBRARY_DIR=$OPENEXR_INSTALL_DIR/lib
 export LD_LIBRARY_PATH=$OPENEXR_ROOT/lib:$LD_LIBRARY_PATH
-
diff --git a/src/cmake/build_OpenEXR.cmake b/src/cmake/build_OpenEXR.cmake
index 03bd63f9a9..86b29e96da 100644
--- a/src/cmake/build_OpenEXR.cmake
+++ b/src/cmake/build_OpenEXR.cmake
@@ -3,10 +3,10 @@
 # https://github.com/AcademySoftwareFoundation/OpenImageIO
 
 
-set_cache (OpenEXR_BUILD_VERSION 3.4.15 "OpenEXR version for local builds")
+set_cache (OpenEXR_BUILD_VERSION 3.5.0 "OpenEXR version for local builds")
 set (OpenEXR_GIT_REPOSITORY "https://github.com/AcademySoftwareFoundation/OpenEXR")
 set (OpenEXR_GIT_TAG "v${OpenEXR_BUILD_VERSION}")
-set (OpenEXR_GIT_COMMIT "e71cdd5d30a146dcb56c5e4c576d9e9d3c45f4fb")
+set (OpenEXR_GIT_COMMIT "5d838e01770cadb8f2a36c0d17018452fa7a3c0c")
 set_cache (OpenEXR_BUILD_SHARED_LIBS ${LOCAL_BUILD_SHARED_LIBS_DEFAULT}
            DOC "Should a local OpenEXR build, if necessary, build shared libraries" ADVANCED)
 
diff --git a/src/cmake/testing.cmake b/src/cmake/testing.cmake
index 92a76c84c8..e0991fb5be 100644
--- a/src/cmake/testing.cmake
+++ b/src/cmake/testing.cmake
@@ -469,6 +469,31 @@ macro (oiio_add_all_tests)
                         IMAGEDIR openexr-images
                         URL http://github.com/AcademySoftwareFoundation/openexr-images)
     endif ()
+
+    # HTJ2K was introduced in OpenEXR v.3.4.0
+    if (OpenEXR_VERSION VERSION_GREATER_EQUAL 3.4.0)
+        if (TEST openexr-compression)
+            set_property (TEST openexr-compression APPEND PROPERTY ENVIRONMENT
+                          "OIIO_OPENEXR_HTJ2K_SUPPORT=1")
+        endif()
+        if (TEST openexr-compression.core)
+            set_property (TEST openexr-compression.core APPEND PROPERTY
+                          ENVIRONMENT "OIIO_OPENEXR_HTJ2K_SUPPORT=1")
+        endif()
+    endif()
+    # New compression tests of zstd and lj2k require OpenEXR main branch,
+    # or latest release or at least V3.5.0
+    if (OpenEXR_VERSION VERSION_GREATER_EQUAL 3.5.0)
+        if (TEST openexr-compression)
+            set_property (TEST openexr-compression APPEND PROPERTY ENVIRONMENT
+                          "OIIO_OPENEXR_LJ2K_ZSTD_SUPPORT=1")
+        endif ()
+        if (TEST openexr-compression.core)
+            set_property (TEST openexr-compression.core APPEND PROPERTY 
+                          ENVIRONMENT "OIIO_OPENEXR_LJ2K_ZSTD_SUPPORT=1")
+        endif ()
+    endif ()
+    
     # Regression test (compiles its own helper and generates its own image)
     # for a partial edge-tile heap overflow in the OpenEXR readers.
     oiio_add_tests (openexr-partialtile)
diff --git a/src/doc/builtinplugins.md b/src/doc/builtinplugins.md
index a354c56050..6a8c9467d6 100644
--- a/src/doc/builtinplugins.md
+++ b/src/doc/builtinplugins.md
@@ -1615,8 +1615,11 @@ The official OpenEXR site is <http://www.openexr.com/>.
    * - ``compression``
      - string
      - one of: ``"none"``, ``"rle"``, ``"zip"``, ``"zips"``, ``"piz"``,
-       ``"pxr24"``, ``"b44"``, ``"b44a"``, ``"dwaa"``, ``"dwab"``, ``"htj2k256"`` or ``"htj2k32"``.
-       (``"htj2k256"`` and ``"htj2k32"`` are only supported with OpenEXR 3.4 or later.)
+       ``"pxr24"``, ``"b44"``, ``"b44a"``, ``"dwaa"``, ``"dwab"``,
+       ``"htj2k256"``, ``"htj2k32"``, ``"lj2k"``, or ``"zstd"``.
+       (``"htj2k256"`` and ``"htj2k32"`` are only supported with OpenEXR 3.4
+       or later; ``"lj2k"`` and ``"zstd"`` are only supported with OpenEXR
+       3.5 or later.)
        If the writer receives a request for a compression type it does not
        recognize or is not supported by the version of OpenEXR on the
        system, it will use ``"zip"`` by default. For ``"dwaa"`` and
@@ -1625,7 +1628,15 @@ The official OpenEXR site is <http://www.openexr.com/>.
        default DWA compression value is 45.) For ``"zip"`` and ``"zips"``
        compression, a level from 1 to 9 may be appended (the default is
        ``"zip:4"``), but note that this is only honored when building
-       against OpenEXR 3.1.3 or later.
+       against OpenEXR 3.1.3 or later. For ``"lj2k"`` (the lossy variant of
+       ``"htj2k256"``), a quality from 1 to 150 may be appended, like
+       ``"lj2k:100"`` (the default is ``"lj2k:110"``). Values from 97 to 150
+       are an OpenEXR-specific extension of the normal 1 to 97 range, giving
+       the higher quality needed for 32-bit float images; values between 90
+       and 110 are recommended for a balance of quality and size. For
+       ``"zstd"``, a compression level from 1 to 22 may be appended, like
+       ``"zstd:10"`` (the default is ``"zstd:5"``). For both ``"lj2k"`` and
+       ``"zstd"``, an out-of-range value falls back to the default.
    * - ``textureformat``
      - string
      - ``"Plain Texture"`` for MIP-mapped OpenEXR files, ``"CubeFace
@@ -3339,4 +3350,3 @@ of the z-buffer. Zfile files use the file extension {file}`.zfile`.
 ```
 
 [st 2065-4]: https://pub.smpte.org/pub/st2065-4/
-
diff --git a/src/openexr.imageio/exrinput.cpp b/src/openexr.imageio/exrinput.cpp
index 0eedff26c7..41f225620b 100644
--- a/src/openexr.imageio/exrinput.cpp
+++ b/src/openexr.imageio/exrinput.cpp
@@ -464,11 +464,22 @@ OpenEXRInput::PartInfo::parse_header(OpenEXRInput* in,
 #endif
 #ifdef IMF_HTJ2K32_COMPRESSION
         case Imf::HTJ2K32_COMPRESSION: comp = "htj2k32"; break;
+#endif
+#ifdef IMF_LJ2K_COMPRESSION
+        case Imf::LJ2K_COMPRESSION: comp = "lj2k"; break;
+#endif
+#ifdef IMF_ZSTD_COMPRESSION
+        case Imf::ZSTD_COMPRESSION: comp = "zstd"; break;
 #endif
         default: break;
         }
-        if (comp)
+        if (comp) {
             spec.attribute("compression", comp);
+        } else {
+            in->errorfmt("Unknown compression code {}",
+                         int(compressattr->value()));
+            return false;
+        }
         if (spec.tile_width == 0 && !spec.deep) {
             // Scanline file: advertise how many scanlines are packed into
             // each compressed chunk, so that callers can align their reads
@@ -480,6 +491,9 @@ OpenEXRInput::PartInfo::parse_header(OpenEXRInput* in,
             if (scansperchunk > 1)
                 spec.attribute("oiio:RowsPerChunk", scansperchunk);
         }
+    } else {
+        in->errorfmt("No compression information found");
+        return false;
     }
 
     for (auto hit = header->begin(); hit != header->end(); ++hit) {
@@ -1105,8 +1119,7 @@ OpenEXRInput::seek_subimage(int subimage, int miplevel)
         if (m_input_multipart)
             header = &(m_input_multipart->header(subimage));
         if (!part.parse_header(this, header)) {
-            errorfmt("Could not seek to subimage={}: unable to parse header",
-                     subimage, miplevel);
+            // Any errors in parse_header will already have called errorfmt
             return false;
         }
         part.initialized = true;
diff --git a/src/openexr.imageio/exrinput_c.cpp b/src/openexr.imageio/exrinput_c.cpp
index 620304767c..639711295b 100644
--- a/src/openexr.imageio/exrinput_c.cpp
+++ b/src/openexr.imageio/exrinput_c.cpp
@@ -16,6 +16,7 @@
 
 #include "exr_pvt.h"
 
+#include <OpenEXR/ImfCRgbaFile.h>
 #include <OpenEXR/openexr.h>
 
 #include "imageio_pvt.h"
@@ -644,11 +645,24 @@ OpenEXRCoreInput::PartInfo::parse_header(OpenEXRCoreInput* in,
 #endif
 #ifdef IMF_HTJ2K32_COMPRESSION
         case EXR_COMPRESSION_HTJ2K32: comp = "htj2k32"; break;
+#endif
+#ifdef IMF_LJ2K_COMPRESSION
+        case EXR_COMPRESSION_LJ2K: comp = "lj2k"; break;
+#endif
+#ifdef IMF_ZSTD_COMPRESSION
+        case EXR_COMPRESSION_ZSTD: comp = "zstd"; break;
 #endif
         default: break;
         }
-        if (comp)
+        if (comp) {
             spec.attribute("compression", comp);
+        } else {
+            in->errorfmt("Unknown compression code {}", int(comptype));
+            return false;
+        }
+    } else {
+        in->errorfmt("No compression information found");
+        return false;
     }
 
     if (spec.tile_width == 0) {
@@ -1195,8 +1209,7 @@ OpenEXRCoreInput::seek_subimage(int subimage, int miplevel)
     PartInfo& part(m_parts[subimage]);
     if (!part.initialized) {
         if (!part.parse_header(this, m_exr_context, subimage, miplevel)) {
-            errorfmt("Could not seek to subimage={}: unable to parse header",
-                     subimage, miplevel);
+            // Any errors in parse_header will already have called errorfmt
             return false;
         }
         part.initialized = true;
diff --git a/src/openexr.imageio/exroutput.cpp b/src/openexr.imageio/exroutput.cpp
index 3a30a41afc..17fd4eee55 100644
--- a/src/openexr.imageio/exroutput.cpp
+++ b/src/openexr.imageio/exroutput.cpp
@@ -1019,6 +1019,22 @@ OpenEXROutput::spec_to_header(ImageSpec& spec, int subimage,
         spec.erase_attribute("openexr:dwaCompressionLevel");
     }
 
+#if OPENEXR_CODED_VERSION >= 30500
+    // OpenEXR 3.5.0 added the support for LJ2K, the lossy variant of HTJ2K256.
+    // Value from 97 to 150 are OpenEXR specific of the normal range of 1 till
+    // 97. This extended range is available to achieve higher quality needed
+    // for 32-bit float images. Values between 90 and 110 are recommended for
+    // a balance of quality and size.
+    if (Strutil::istarts_with(comp, "lj2k")) {
+        header.lossyHTJ2KQuality() = (qual >= 1 && qual <= 150) ? qual : 110;
+    }
+
+    // OpenEXR 3.5.0 added an API for setting the zstd compression/quality
+    // level in the Header object. Default value is 5.
+    if (Strutil::istarts_with(comp, "zstd")) {
+        header.zstdCompressionLevel() = (qual >= 1 && qual <= 22) ? qual : 5;
+    }
+#endif
     // Default to increasingY line order
     if (!spec.find_attribute("openexr:lineOrder"))
         spec.attribute("openexr:lineOrder", "increasingY");
@@ -1268,6 +1284,14 @@ OpenEXROutput::put_parameter(const std::string& name, TypeDesc type,
 #ifdef IMF_HTJ2K32_COMPRESSION
             else if (Strutil::iequals(str, "htj2k32"))
                 header.compression() = Imf::HTJ2K32_COMPRESSION;
+#endif
+#ifdef IMF_LJ2K_COMPRESSION
+            else if (Strutil::iequals(str, "lj2k"))
+                header.compression() = Imf::LJ2K_COMPRESSION;
+#endif
+#ifdef IMF_ZSTD_COMPRESSION
+            else if (Strutil::iequals(str, "zstd"))
+                header.compression() = Imf::ZSTD_COMPRESSION;
 #endif
         }
         return true;
diff --git a/testsuite/openexr-compression/ref/out-exr3.1.txt b/testsuite/openexr-compression/ref/out-exr3.1.txt
new file mode 100644
index 0000000000..e1389e32af
--- /dev/null
+++ b/testsuite/openexr-compression/ref/out-exr3.1.txt
@@ -0,0 +1,30 @@
+out-none.exr compression none
+out-rle.exr compression rle
+out-zips.exr compression zips
+out-zip.exr compression zip
+out-piz.exr compression piz
+out-pxr24.exr compression pxr24
+out-b44.exr compression b44
+out-b44a.exr compression b44a
+out-dwaa.exr compression dwaa
+out-dwab.exr compression dwab
+Comparing "out-none.exr" and "ref/out-zip.exr"
+PASS
+Comparing "out-rle.exr" and "ref/out-zip.exr"
+PASS
+Comparing "out-zips.exr" and "ref/out-zip.exr"
+PASS
+Comparing "out-zip.exr" and "ref/out-zip.exr"
+PASS
+Comparing "out-piz.exr" and "ref/out-zip.exr"
+PASS
+Comparing "out-pxr24.exr" and "ref/out-zip.exr"
+PASS
+Comparing "out-b44.exr" and "ref/out-b44.exr"
+PASS
+Comparing "out-b44a.exr" and "ref/out-b44.exr"
+PASS
+Comparing "out-dwaa.exr" and "ref/out-dwaa.exr"
+PASS
+Comparing "out-dwab.exr" and "ref/out-dwaa.exr"
+PASS
diff --git a/testsuite/openexr-compression/ref/out-exr3.4.txt b/testsuite/openexr-compression/ref/out-exr3.4.txt
new file mode 100644
index 0000000000..70ea194e87
--- /dev/null
+++ b/testsuite/openexr-compression/ref/out-exr3.4.txt
@@ -0,0 +1,36 @@
+out-none.exr compression none
+out-rle.exr compression rle
+out-zips.exr compression zips
+out-zip.exr compression zip
+out-piz.exr compression piz
+out-pxr24.exr compression pxr24
+out-b44.exr compression b44
+out-b44a.exr compression b44a
+out-dwaa.exr compression dwaa
+out-dwab.exr compression dwab
+out-htj2k32.exr compression htj2k32
+out-htj2k256.exr compression htj2k256
+Comparing "out-none.exr" and "ref/out-zip.exr"
+PASS
+Comparing "out-rle.exr" and "ref/out-zip.exr"
+PASS
+Comparing "out-zips.exr" and "ref/out-zip.exr"
+PASS
+Comparing "out-zip.exr" and "ref/out-zip.exr"
+PASS
+Comparing "out-piz.exr" and "ref/out-zip.exr"
+PASS
+Comparing "out-pxr24.exr" and "ref/out-zip.exr"
+PASS
+Comparing "out-b44.exr" and "ref/out-b44.exr"
+PASS
+Comparing "out-b44a.exr" and "ref/out-b44.exr"
+PASS
+Comparing "out-dwaa.exr" and "ref/out-dwaa.exr"
+PASS
+Comparing "out-dwab.exr" and "ref/out-dwaa.exr"
+PASS
+Comparing "out-htj2k32.exr" and "ref/out-zip.exr"
+PASS
+Comparing "out-htj2k256.exr" and "ref/out-zip.exr"
+PASS
diff --git a/testsuite/openexr-compression/ref/out-lj2k.exr b/testsuite/openexr-compression/ref/out-lj2k.exr
new file mode 100644
index 0000000000..7478e6291a
Binary files /dev/null and b/testsuite/openexr-compression/ref/out-lj2k.exr differ
diff --git a/testsuite/openexr-compression/ref/out.txt b/testsuite/openexr-compression/ref/out.txt
index e1389e32af..eda68ff448 100644
--- a/testsuite/openexr-compression/ref/out.txt
+++ b/testsuite/openexr-compression/ref/out.txt
@@ -8,6 +8,10 @@ out-b44.exr compression b44
 out-b44a.exr compression b44a
 out-dwaa.exr compression dwaa
 out-dwab.exr compression dwab
+out-htj2k32.exr compression htj2k32
+out-htj2k256.exr compression htj2k256
+out-lj2k.exr compression lj2k
+out-zstd.exr compression zstd
 Comparing "out-none.exr" and "ref/out-zip.exr"
 PASS
 Comparing "out-rle.exr" and "ref/out-zip.exr"
@@ -28,3 +32,11 @@ Comparing "out-dwaa.exr" and "ref/out-dwaa.exr"
 PASS
 Comparing "out-dwab.exr" and "ref/out-dwaa.exr"
 PASS
+Comparing "out-htj2k32.exr" and "ref/out-zip.exr"
+PASS
+Comparing "out-htj2k256.exr" and "ref/out-zip.exr"
+PASS
+Comparing "out-lj2k.exr" and "ref/out-lj2k.exr"
+PASS
+Comparing "out-zstd.exr" and "ref/out-zip.exr"
+PASS
diff --git a/testsuite/openexr-compression/run.py b/testsuite/openexr-compression/run.py
index d4019d9778..0e1882db46 100755
--- a/testsuite/openexr-compression/run.py
+++ b/testsuite/openexr-compression/run.py
@@ -4,6 +4,7 @@
 # SPDX-License-Identifier: Apache-2.0
 # https://github.com/AcademySoftwareFoundation/OpenImageIO
 
+import os
 
 imagedir = "../common"
 
@@ -20,6 +21,11 @@
     "dwab",
 ]
 
+if os.getenv("OIIO_OPENEXR_HTJ2K_SUPPORT") == "1":
+    compressions += ["htj2k32", "htj2k256"]
+if os.getenv("OIIO_OPENEXR_LJ2K_ZSTD_SUPPORT") == "1":
+    compressions += ["lj2k", "zstd"]
+
 anymatch = True
 outputs = []
 for c in compressions: