How to plot two distribution curves in a faceted way in R/ggplot2?
I would separate the creation of the data from the plotting operation, if I were you. ggplot2::facet_wrap allows you to plot each of the cumulative distributions in each own panel. Here is how I would do it.

pgammaX &lt;- function(x) pgamma(x, shape = 64.57849, scale = 0.08854802)

Gamma &lt;- pgammaX(seq(from=4, to = 8, by = 0.1))
Normal &lt;- pnorm(seq(from=-4, to = 3.9, by = 0.1))

data &lt;- data_frame(
  x = seq(-4,8,by=0.1),
  y = c(Normal, Gamma),
  # use factor to make the plot for Normal to appear first
  distribution = factor(c(rep(c("Normal", "Gamma"), 
                          times = c(length(Normal), length(Gamma)))),
                          levels = c("Normal", "Gamma"))
)

library(dplyr)    
library(ggplot2)

data %&gt;%  ggplot(aes(x, y)) + 
  geom_line() + 
  # use facet_wrap to plot each cummulative distribution in each own panel      
  facet_wrap(~distribution, scales = "free_x")