diff --git a/biology/gemma/Makefile b/biology/gemma/Makefile
index 72634c0e3506..062a368a2c2f 100644
--- a/biology/gemma/Makefile
+++ b/biology/gemma/Makefile
@@ -26,6 +26,8 @@ LDFLAGS+=	-lopenblas
 
 OPTIONS_DEFINE=	EXAMPLES
 
+BROKEN=		Conflict between math/gsl and math/cblas constant redeclarations
+
 pre-configure:
 	@${REINPLACE_CMD} -e 's|../bin/gemma|../gemma|' ${WRKSRC}/test/*.sh
 
diff --git a/math/gsl/Makefile b/math/gsl/Makefile
index 7cc00fab520b..558da29aee96 100644
--- a/math/gsl/Makefile
+++ b/math/gsl/Makefile
@@ -2,8 +2,7 @@
 # $FreeBSD$
 
 PORTNAME=	gsl
-PORTVERSION=	2.5
-PORTREVISION=	1
+PORTVERSION=	2.6
 CATEGORIES=	math
 MASTER_SITES=	GNU
 
diff --git a/math/gsl/distinfo b/math/gsl/distinfo
index 51580cef2e74..bbf53b1b2661 100644
--- a/math/gsl/distinfo
+++ b/math/gsl/distinfo
@@ -1,3 +1,3 @@
-TIMESTAMP = 1529158403
-SHA256 (gsl-2.5.tar.gz) = 0460ad7c2542caaddc6729762952d345374784100223995eb14d614861f2258d
-SIZE (gsl-2.5.tar.gz) = 7303881
+TIMESTAMP = 1566551853
+SHA256 (gsl-2.6.tar.gz) = b782339fc7a38fe17689cb39966c4d821236c28018b6593ddb6fd59ee40786a8
+SIZE (gsl-2.6.tar.gz) = 7398548
diff --git a/math/gsl/pkg-plist b/math/gsl/pkg-plist
index de5c97ccdbce..507c6fd2ee47 100644
--- a/math/gsl/pkg-plist
+++ b/math/gsl/pkg-plist
@@ -19,6 +19,10 @@ include/gsl/gsl_block_uint.h
 include/gsl/gsl_block_ulong.h
 include/gsl/gsl_block_ushort.h
 include/gsl/gsl_bspline.h
+include/gsl/gsl_bst.h
+include/gsl/gsl_bst_avl.h
+include/gsl/gsl_bst_rb.h
+include/gsl/gsl_bst_types.h
 include/gsl/gsl_cblas.h
 include/gsl/gsl_cdf.h
 include/gsl/gsl_chebyshev.h
@@ -213,6 +217,20 @@ include/gsl/gsl_splinalg.h
 include/gsl/gsl_spline.h
 include/gsl/gsl_spline2d.h
 include/gsl/gsl_spmatrix.h
+include/gsl/gsl_spmatrix_char.h
+include/gsl/gsl_spmatrix_complex_double.h
+include/gsl/gsl_spmatrix_complex_float.h
+include/gsl/gsl_spmatrix_complex_long_double.h
+include/gsl/gsl_spmatrix_double.h
+include/gsl/gsl_spmatrix_float.h
+include/gsl/gsl_spmatrix_int.h
+include/gsl/gsl_spmatrix_long.h
+include/gsl/gsl_spmatrix_long_double.h
+include/gsl/gsl_spmatrix_short.h
+include/gsl/gsl_spmatrix_uchar.h
+include/gsl/gsl_spmatrix_uint.h
+include/gsl/gsl_spmatrix_ulong.h
+include/gsl/gsl_spmatrix_ushort.h
 include/gsl/gsl_statistics.h
 include/gsl/gsl_statistics_char.h
 include/gsl/gsl_statistics_double.h
@@ -250,8 +268,8 @@ include/gsl/gsl_wavelet.h
 include/gsl/gsl_wavelet2d.h
 lib/libgsl.a
 lib/libgsl.so
-lib/libgsl.so.23
-lib/libgsl.so.23.1.0
+lib/libgsl.so.25
+lib/libgsl.so.25.0.0
 lib/libgslcblas.a
 lib/libgslcblas.so
 lib/libgslcblas.so.0
diff --git a/math/p5-Math-GSL/Makefile b/math/p5-Math-GSL/Makefile
index 4bfaec297e2e..b27ede1aa8a9 100644
--- a/math/p5-Math-GSL/Makefile
+++ b/math/p5-Math-GSL/Makefile
@@ -23,6 +23,8 @@ TEST_DEPENDS=	p5-Test-Class>=0.12:devel/p5-Test-Class \
 USES=		perl5
 USE_PERL5=	modbuild
 
+BROKEN=		Does not work with gsl-2.6
+
 post-install:
 	${FIND} ${STAGEDIR}${PREFIX}/${SITE_ARCH_REL}/auto/Math/GSL/ -name "*.so" -exec ${STRIP_CMD} {} +