diff --git a/share/completions/cjxl.fish b/share/completions/cjxl.fish
new file mode 100644
index 000000000..44ac85edc
--- /dev/null
+++ b/share/completions/cjxl.fish
@@ -0,0 +1,101 @@
+# Completions for the JPEG XL Reference Software (https://gitlab.com/wg1/jpeg-xl)
+
+complete -c cjxl -s V -l version -d "Print version number"
+complete -c cjxl -l quiet -d "Be more silent"
+complete -c cjxl -l container -d "Encode using container format"
+complete -x -c cjxl -l print_profile -a "0 1" -d "Print timing information"
+complete -x -c cjxl -s d -l distance -a "
+    0.0\t'Mathematically lossless'
+    1.0\t'Visually lossless'
+    " -d "Butteraugli distance"
+complete -x -c cjxl -l target_size -d "Target file size (based on bytes)"
+complete -x -c cjxl -l target_bpp -d "Target file size (based on BPP)"
+complete -x -c cjxl -s q -l quality -a "
+    (seq 0 99)
+    100\t'Mathematically lossless'
+    " -d "Quality setting"
+complete -x -c cjxl -s s -l speed -a "
+    3\tFastest falcon\tFastest
+    4 cheetah
+    5 hare
+    6 wombat
+    7\tDefault squirrel\tDefault
+    8 kitten
+    9\tSlowest tortoise\tSlowest
+    " -d "Encoder speed setting"
+complete -c cjxl -s p -l progressive -d "Enable progressive decoding"
+complete -c cjxl -l middleout -d "Put center groups first in the file"
+complete -c cjxl -l progressive_ac -d "Use the progressive mode for AC"
+complete -c cjxl -l qprogressive_ac -d "Use the progressive mode for AC"
+complete -x -c cjxl -l progressive_dc -d "Use progressive mode for DC"
+complete -c cjxl -s m -l modular -d "Use the modular mode"
+complete -c cjxl -l use_new_heuristics -d "Use new encoder heuristics"
+complete -c cjxl -s j -l jpeg_transcode -d "Do lossy transcode of input JPEG file"
+complete -x -c cjxl -l num_threads -d "Number of worker threads"
+complete -x -c cjxl -l num_reps -d "How many times to compress"
+complete -x -c cjxl -l noise -a "
+    0\tEnable
+    1\tDisable
+    " -d "Force noise generation"
+complete -x -c cjxl -l dots -a "
+    0\tEnable
+    1\tDisable
+    " -d "Force dots generation"
+complete -x -c cjxl -l patches -a "
+    0\tEnable
+    1\tDisable
+    " -d "Force patches generation"
+complete -x -c cjxl -l resampling -a "1 2 4 8" -d "Subsample all color channels"
+complete -x -c cjxl -l epf -d "Edge preserving filter level"
+complete -x -c cjxl -l gaborish -a "0 1" -d "Force disable gaborish"
+complete -x -c cjxl -l intensity_target -d "Intensity target of monitor in nits"
+complete -x -c cjxl -l saliency_num_progressive_steps
+complete -x -c cjxl -l saliency_map_filename
+complete -x -c cjxl -l saliency_threshold
+complete -x -c cjxl -s x -l dec-hints
+complete -x -c cjxl -l override_bitdepth -a "
+    0\t'Use from image'
+    (seq 1 32)\tOverride
+    " -d "Store the given bit depth in the metadata"
+complete -x -c cjxl -s c -l colortransform -a "
+    0\tXYB
+    1\tNone
+    2\tYCbCr"
+complete -x -c cjxl -s Q -l mquality -d "Lossy quality"
+complete -x -c cjxl -s I -l iterations -d "Fraction of pixels used to learn MA trees"
+complete -x -c cjxl -s C -l colorspace -a "
+    0\tRGB
+    1\tYCoCg
+    (seq 2 37)\tRCT
+    " -d "Color transform"
+complete -x -c cjxl -s g -l group-size -d "Set group size"
+complete -x -c cjxl -s P -l predictor -a "
+    0\tZero
+    1\tLeft
+    2\tTop
+    3\tAverage0
+    4\tSelect
+    5\tGradient
+    6\tWeighted
+    7\tTopRight
+    8\tTopLeft
+    9\tLeftLeft
+    10\tAverage1
+    11\tAverage2
+    12\tAverage3
+    13\t'TopTop predictive average'
+    14\t'Mix Gradient and Weighted'
+    15\t'Mix everything'
+    " -d "Predictor to use"
+complete -x -c cjxl -s E -l extra-properties -d "Number of extra MA tree properties"
+complete -x -c cjxl -s N -l near-lossless -d "Apply near-lossless preprocessing"
+complete -x -c cjxl -l palette -d "Use a palette"
+complete -c cjxl -l lossy-palette -d "Quantize to a lossy palette"
+complete -x -c cjxl -s X -l pre-compact -d "Compact channels (globally)"
+complete -x -c cjxl -s Y -l post-compact -d "Compact channels (per-group)"
+complete -x -c cjxl -s R -l responsive -a "
+    0\tFalse
+    1\tTrue
+    " -d "Do squeeze transform"
+complete -c cjxl -s v -l verbose -d "Verbose output"
+complete -c cjxl -s h -l help -d "Print help message"
diff --git a/share/completions/djxl.fish b/share/completions/djxl.fish
new file mode 100644
index 000000000..c5b9c6506
--- /dev/null
+++ b/share/completions/djxl.fish
@@ -0,0 +1,17 @@
+# Completions for the JPEG XL Reference Software (https://gitlab.com/wg1/jpeg-xl)
+
+complete -c djxl -s V -l version -d "Print version number"
+complete -x -c djxl -l num_reps
+complete -c djxl -l use_sjpeg -d "Use sjpeg instead of libjpeg"
+complete -x -c djxl -l jpeg_quality -d "JPEG output quality"
+complete -x -c djxl -l num_threads -d "The number of threads to use"
+complete -x -c djxl -l print_profile -a "0 1" -d "Print timing information"
+complete -x -c djxl -l print_info -a "0 1" -d "Print AuxOut"
+complete -x -c djxl -l bits_per_sample
+complete -x -c djxl -l color_space
+complete -x -c djxl -s s -l downsampling -a "1 2 4 8 16" -d "Maximum permissible downsampling factor"
+complete -c djxl -l allow_partial_files -d "Allow decoding of truncated files"
+complete -c djxl -l allow_more_progressive_steps -d "Allow decoding more progressive steps"
+complete -c djxl -s j -l jpeg -d "Decode directly to JPEG"
+complete -c djxl -l print_read_bytes -d "Print total number of decoded bytes"
+complete -c djxl -s h -l help -d "Print help message"