The primary reference which governs post-graduate studies in the CF is
CFAO 9-33 -- POST-GRADUATE TRAINING PROGRAMS REGULAR FORCE AND PRIMARY RESERVE. It outlines 4 separate programs. The first, the General Program is the one most used.
Various organizations within the CF have identified a requirement to have someone working for them with a specific post-graduate qualification, and are willing to foot the bill. The members gets education subsidized, and then goes to work for the organization that sponsored them for a specific period of time, typically 2 years. This incurs obligatory service. As well, the program is typically only open for a specific degree at a specific institution, although some do mention the degree can be taken at "Any Canadian University".
The eligibility requirements are as follows:
9. To be considered for selection for PGT, an officer will normally:
a. by 1 Sep of the year in which the PG training is to commence, have completed three years commissioned service;
b. have sufficient time remaining in his present period of service, after graduation, to complete the obligatory service resulting from participation in a PG programme, as prescribed in CFAO 15-7;
c. meet the appropriate educational prerequisites; and
d. meet such other conditions as the CDS may prescribe.
The second program outlined is the "Training on Scholarship Programme", and is the only program where one can typically proceed on subsidized post-graduate education immediately after finishing an undergraduate degree via ROTP or UTPNCM. It is a tough one to get authorization for, and is only for personnel who have won a "prestigious scholarship." Specifically mentioned in the CFAO is that "Preference will be given to those scholarships that are universally recognized, such as the Rhodes scholarship." As you can imagine, this program is bloody rare.
This article mentions that RMC has only had a total of 12 Rhodes scholars ever. The most recent, in 2008, would not have been eligible for this program anyways, as he was at RMC via the Reserve Entry Training Plan vice ROTP. The one previous to that was in 1987. I'm sure there's a few scattered cases of this program being used for prestigious scholarships that aren't at Oxford, but still, it's a rare event.
The third program outlined is "Training Under The DND Military and Strategic Studies Programme", and I believe it is for those senior (or soon to be) officers being sent to staff college. You need at least 10 years commissioned service to be eligible.
The fourth is "Post-Graduate Training - Primary Reserve", which allows for reserve officers to receive post-gradate training at RMC in Military History, War Studies, or Engineering and Science. This is paid for by their reserve unit.
These are the options for full-time post-graduate education. As well, there is the option of doing part-time education on top of your full-time job, via the "
Advanced Degree - Part-Time Programme for Regular force Officers" program, outlined in CF Military Personnel Instructions 18/04. For this one you must be Reg Force, Trade Qualified, not on LWOP, not already have a Master's degree or higher, and be applying for a degree which "specified military, occupational or organizational requirement". Approval must come from your L1 or a designated authority no lower than BGen/Cmdre.
Oh yes. Also, each of these will incur additional obligatory service. Any full-time post grad is at the same rate as ROTP. Any part-time post grad incurs 1 additional month of obligatory service per $2,000 subsidized.